This invention has application in the distribution of digital video on demand services
and other digital services everywhere
in a consumer area.
With the advent of cable modems, there is the possibility of adding digital data
Deliver high rates from content providers and Internet over cable TV systems.
Many different services will be delivered digitally,
one of these is video-on-demand and high definition digital TV data. One
other digital service, at least for work facilities
is useful, is videoconferencing. Other digital services that
more and more useful in the future
are high speed connection with a working LAN of
at home for
Telecommunications, high-speed Internet access, distance learning, multimedia presentations
to remote and / or distributed audiences, etc.
Development of cable modems has provided high-speed data over 10MB / sec channels to customer premises over hybrid fiber coaxial cable TV distribution network
But as soon as the digital data reaches a customer premises, they have to
still distributed and converted into a suitable format for use
by the user on a TV, a telephone, a videophone, a
Computer, a network computer, a fax, a DVD recorder
and other peripherals,
which will be developed in the future.
the telephone companies have developed digital subscriber line technologies,
such as. asymmetrical digital subscriber line (ADSL),
High-bit rate digital subscriber line technology, ISDN and
ISDL, rate-adaptive digital subscriber line (RADSL),
balanced digital subscriber line (SDSL), high-speed DSL
(VDSL). These different technologies are described in
Muller, Desktop Encyclopedia of Telecommunications, pages 93-95 (McGraw
Hill 1998) ISBN 0-07-044457-9 and Clayton, Illustrated Telecom Dictionary,
(McGraw Hill 1998) ISBN 0-07-012063-3 and Horak, Communications
Systems and Networks, Voice, Data and Broadband Technologies, (M & T Books, Foster
City, approx. 1997) ISBN 1-55851-485-6, the entirety of these
is hereby incorporated by reference. These digital subscriber line technologies
will soon be able to digital language, data and image information
from different servers as well as high-speed Internet access
to the participant area
Standard telephone copper-twisted pairs already in service
Are ground and that everyone already has. Some of these technologies
are fast enough to also deliver video on demand,
Data rates of about
2 megabits / sec needed.
were also introduced in 1994,
Digital Broadcast Satellite Services
(DBS), such as DirecTV (offered by Hughes Electronics and Thomson
Multimedia). DBS services can
already or will soon provide video on demand, internet connectivity
and multimedia applications, all with the high picture quality, the digital
Technology provides. Videoconferencing via DirecPC service may also be like this
to be provided soon. DierecTV delivers 175 channels of digital quality programs over one
18 inch glass antenna,
a digital set-top decoder box and a remote control. An access card
allows payment information to be obtained through the set-top decoder box and
is being downloaded by the PSTN to a pay-TV payment center,
which was requested by a user. In addition, DirecPC technology allows
High-speed (400 KB / sec) Internet access to PCs in the customer premises
using the DBS bowl and
Koaxialkabelverteilungsnetzwerk. An expansion card couples
the PC I / O buses to the coaxial cable distribution network of the DBS system.
A modem is used by the PC to establish a connection
to the Internet service provider (ISP), who then sends Internet data
to the PC via
an uplink to the satellite and then down to the user's bowl.
Problem that users of digital data delivery services are soon facing
be, is as follows. There is great uncertainty about which subscriber data delivery services
the most reliable,
the best performing and cheapest versions of any type service
be deployed. That's why there is a need for one there
a user to be able to view all the different subscriber service data delivery options
to make and save the data cheaply over theirs
to distribute to all the different peripherals that
Computers, phones, video phones, etc. To do this, it becomes necessary
be to have a kind of circuit that is connected to the different ones
Dock Subscriber Service Digital Data Delivery Networks
can, and at least a local network that goes through the whole
Home of the user is running
and makes all necessary protocol conversions and packet, cell
or frame reassembly
and encapsulate in packets of the type used on the LAN
how the remote 810 ADSL router made by 3Com exists
These routers can
pair a local Ethernet network to ADSL lines so that POTS voice conversion
can occur simultaneously while
the internet is searched. The Remote 810 ADSL Router has one
built-in 4-port 10Base-T hub to pair multiple PCs,
who share the same ADSL line. The router supports up
to 16 simultaneous simultaneous connections to multiple destinations
on the internet and can bridge functions
3Com also manufactures SDSL routers such as the OfficeConnect Remote 840 SDSL,
support the applications
which may require high bandwidths in both directions, like
e.g. Video conferencing, remote training, web events, e-commerce and
other multimedia applications.
Prior art, such as the 3Com PathBuilder S700 WAN switch
exists, the traffic over
Wide area networks concentrated, aggregated and switched. The PathBuilder S700 WAN
Can converge voice, video and data applications - including frame
Relay, ATM and SONET - up
a common network. Up to 100 interfaces are supported. advanced
Traffic management features such as e.g. Traffic forms, priority queues
and multicasts guarantee the right amount of bandwidth for every application
and let you build and manage your WAN infrastructure. Of the
Switch has a future proof substructure with a modular construction,
around the initial one
and to provide a migration path to future
To harbor growth. The switch has individual application modules
to provide their own interfaces to a variety of
Campus network technologies such as LANs, muxes, routers, SNA applications,
and PBXs. Each application module adjusts communication traffic
to the cell-based bus board and transports it via the PathBuilder S700 Switch Cell Bus
to the appropriate remote interface connections that provide a comprehensive
Provide a range of campus and wide-area interfaces.
A T1 / UNI module supported
inverse multiplexing for
ATM at speed ranges from 1.5 Mbps to 16 Mbps. One
Migration to T3 / E3 or OC-3 services when bandwidth requirements
increase. Distributed processing is implemented by placement
a RISC processor on each application module to be scalable
and to provide wire speed communication.
The 3COM Pathbuilder S700 WAN Switch lacks the ability to
to connect to ADSL lines, cable modems, satellite dishes, wireless
terrestrial microwave links or other subscriber network services,
which may become available in the future, such as digital data delivery over the power lines.
The 3COM Pathbuilder S700 WAN Switch
is a switch of a professional level that is not affordable
is for the
average home network customers. In short, it is believed
that it is present
There are no gateways or routers that are able to handle a local one
Network like an ethernet to any public service telephone network
to couple and the the technology of ADSL modems, cable modems
and satellite DirectPC decoder boxes with IP video and IP telephone interfaces
and embody and combine switching, routing and protocol conversion capabilities.
the current one
Climate of Deregulation is a fierce competition for provision
from telecommunications services to customers. Many alternative
Distribution networks for
digital data has either already been developed or is
in development. For example, in the near future, the digital
Data delivery services that have just been described by
the PSTN and CATV HFC distribution facilities are delivered,
also compete with wireless subscriber line delivery networks,
provided by personal communication service (PCS) companies and data delivery services
in development by the electrical power supply facilities.
The problem is that the customer has no way of knowing which services will provide the highest reliability, highest quality, and least expensive delivery mechanism for telephone and fax services, e-mail, distance learning, videoconferencing, high-speed world-wide-web access, Video on Demand, Remote LAN for Telecom and Multimedia Services. Furthermore, over time, as each of the subscriber networks evolves and competitive pressures reduce prices, it is possible that who was once the best provider of, for example, video on demand (hereafter referred to as VOD) is no longer the best provider, but rather it is another technology. As another example, ADSL does not have sufficient upstream bandwidth when video telephony becomes a popular application, whereas cable modems do. However, variable bit rates, MPEG2 and advanced video compression technologies may save ADSL as video conferencing becomes large, and high speed ADSL may be suitable for serving this application. The problem this poses for customers is that they do not want to invest in a technology for their home networks that only couples to ADSL or cable modems, and then faces are expecting an expensive replacement for their home network equipment to pair their LAN with a new subscriber service digital data delivery network.
another example relates to supplying consumers with simple
Telephone service (POTS) via
Cable modem versus ADSL. Disconnecting a CATV line in the
or losing an aerial cable during a storm
Separate service from the entire neighborhood. This means that
everyone in the neighborhood who gets their phone service via cable modem
left without telephone service
is until the break is repaired. In contrast, ADSL is one
Point-to-point technology that only causes a customer phone service
loses if the line is interrupted. A well-maintained HFC CATV network
can make some of these problems obsolete, but this is unclear
because there is no big one there
Field experience was gained in POTS via HFC.
a customer will not know if he should buy a gateway, the
can connect to an ADSL modem or an HDSL modem or a cable modem,
until mistakes are eliminated and competitive factors come into play
and make it clear which supply network is the best, least expensive
provides this application.
One thing is clear: The above services are required
and the customer wants
to be able to take advantage of the best delivery mechanism
Service, and would like
to be able to easily switch between delivery services because
Competition caused price adjustments.
these services will occur on many different media
in many different package formats or using many
different protocols, is a problem for the user in deciding
emerged, which type of home network data distribution system
he should buy and install. For example, it will be different there
Give package and cell sizes,
and different header structures, different types of
Compression and different protocols will be used.
The user wants
and convenient distribution of data that each encode these services over its
entire space too
the various peripherals,
such as digital VCRs, DVD recorders / players, TVs, fax machines, computers,
Phones, etc., who need the data without different
Gateways and local network for
to require every type of data delivery service. Furthermore, the user likes
use some services and cable modem for other services and wireless
Local loop or satellite downlinks or others
Data delivery network options for
use other services.
related problem is in the field of video conferencing. Present are
Videophones by AT & T
offered a commercial failure due to the low
of two frames per second, which are available via standard twisted pairs.
ISDN circuits can be used
Videoconferencing, and ISDN video phones are available, and their details become
hereby incorporated by reference. However, the high costs
of ISDN and its low availability
Households delayed the acceptance of ISDN video conferencing. Switched 56/64 Kbps circuits
be used for
Videoconferencing by connecting or grouping in multiple channels. Switched 384 Kbps connections
also be provided on the basis of fractal DS1
or through ISDN PRI channels in one
Channel group known as HO. However, the costs exist
and availability issues,
delay the ISDN conferences,
switched 56/64 and switched 384 Kbps services.
DS-1 facilities Full-motion, high-quality video conferencing over dedicated networks
Rates of up to 2,048 Mbps for
E1 and 1.544 Mbps for
T1. However, DS-1 facilities are expensive and not widely used,
and even if they are for
Organizations with DS-2 backbones are affordable, they are outside
the range of the home network customer.
such as ADSL, B-ISDN, HFC and cable modems, satellite etc.
probably much more comfortable and affordable ways for delivery
video conferencing services
ATM operated at DS-1 or
DS-3 or high speeds.
Therefore, a need has arisen for a system that interfaces with many different subscriber service data delivery networks and that can distribute digital data about customer premises in an economical manner to all the peripheral devices that need the data using a common protocol and addressing scheme , Preferably, the system will have an economical and reliable local area network on the customer premises side and will have the flexibility to couple and translate data types to many different subscriber service data delivery networks, whatever packet / frame / frame types and protocols are used through the data delivery network, without significant effort of reconfiguration or purchase of new equipment or software, every time a data delivery network option emerges that is better, cheaper, or more reliable than the customer's current service provider.
It is known that a prior art document WO 99/44363 A
Method and apparatus disclosed for synchronizing sound
and images in a real-time multimedia communication via a
Network gateway. From an audio signal and a video signal will be
at least the audio signal provided as an input to the gateway;
optionally also the video signal, so that the signal (s) routed
is / are passed through the gateway to the multimedia terminal. Any deviation will
detected in the synchronization between the audible and visible outputs of the
and the video device,
which are caused, at least in part, by the intrinsic gateway processing delay (s).
A variable delay
is adapted in the gateway on a signal being routed
through the gateway until the audible
and visible issues from different devices effectively
are synchronized. The variable delay is stored in the gateway
for future use.
According to one
first aspect of the present invention, there is provided a gateway device,
whose characteristic features are those that claim
1 are described.
According to one
second aspect of the invention, there is provided a process,
which runs through a gateway
whose characteristic features are those in
Claim 28 are described.
Short description of
1 Figure 4 is a diagram of a prior art connection between the Internet and a home-local area network via a cable modem and the HFC of a CATV system.
2 Figure 4 is a diagram of a prior art connection between the Internet and a home-local network via an ADSL modem.
3 FIG. 10 is a diagram of a home network having a gateway within the class of the invention which couples to any one of a number of different subscriber service data delivery facilities external to a customer premises, to one or more local area networks providing digital data from the external Network to one or more devices in the customer premises, which are coupled to the local networks. The gateway makes the necessary protocol conversions and translations between the protocols and packet formats of the local network and the protocols and packet formats of the subscriber-service-data-delivery-external networks.
4A and 4B FIG. 12 are detailed diagrams of a gateway having ADSL satellite cable and broadcast TV antenna interface circuitry.
5 Figure 10 is a block diagram of a video adapter for coupling a local area network to a television.
6A - 6E are flowcharts of a drag-technology video-on-demand process.
7 is a flow chart of a broadband Internet access process.
8th is a block diagram of a modular construction of the gateway.
the preferred and alternative embodiments
1 Figure 4 is a diagram of a prior art connection between the Internet and a home-local area network via a cable modem and an HFC of a CATV system. The internet is shown as a cloud 11 , An IP router 13 in the headend device 15 An Internet service provider bi-directionally couples IP packets to the Internet using the TCP transport protocol. An optional local proxy server 17 , The proxy server is coupled to the IP router and provides local network content as well as recordings of very popular web pages in the cache, such as Yahoo or CNN news, etc., so that they are sent to cable modem subscribers at a faster rate can be. A control unit 19 concentrates all IP traffic from the subscribers who are paired to the HFC network and sends it to the IP router 13 and distributes packets from the IP router to the various fiber optic links, including the line 21 typical. The fiber optic link couples the head end to fiber nodes, of which the node 23 typical. Each fiber node couples the fiber optic link to a coaxial cable feed branch from which the branch 25 typical. Each feed branch has at least one bidirectional amplifier, of which the amplifier 27 typical. Each feed branch is coupled to a plurality of take-off lines, of which the decrease 29 typical is that couple the diversion to a cable modem in the customer premises. The cable modem 31 is typical and may be any of the cable modems identified below. The cable modem has a 10Base-T output port coupled to an Ethernet LAN 33 that passes through the home to peripherals, such as TV 39 , Phone 37 and personal computers 35 , A typical example of a cable modem 31 is the US robotics cable modem CMX. This cable modem will work with any cable system that complies with the MCNS data-over-cable specification. This cable modem comes with an Ethernet network interface card and is compatible with the Windows and Macintosh operating systems.
Referring to 2 There is a state-of-the-art connection between the Internet and a local area network in a home shown over the telephone system using an ADSL modem. The Internet 11 is coupled to the IP router 13 via DS1 (1.544 Mbps supportive of 5 or more continuous users or up to 55 users with 10% usage), DS3 (support 45 Mbps up to 1500 subscribers) or OC3 connections. The optional proxy server 17 serves the same function as it does in the cable modem system of 1 serves. The ADSL modems 41 and 42 at the subscriber premises 45 and the central office 47 connect to the twisted pairs of copper wires originally used for POTS. A POTS splitter, not shown, transparently forwards the analog voice to the POTS central office at a frequency below the ADSL range. The ADSL modem 41 connects directly to the Ethernet port of a personal computer or to an Ethernet hub. The access switch 53 serves to concentrate access lines from the ADSL modems, such as 43 in router ports from IP router 13 , It is likely that the access adapter 53 Includes ATM switching structure. The ADSL modem 41 For example, the 3Com HomeConnect ADSL modem can be Ethernet or any equivalent ADSL modem.
Referring to 3 there is shown a diagram of a home network having a gateway within the class of the invention which couples any one of a number of different subscriber service data delivery networks external to a customer premises to one or more local area networks providing digital data from the external ones Networks to one or more devices in the customer premises that are linked to the local area networks. The gateway makes the necessary protocol conversions and translations between the protocols and the packet formats of the local network and the protocols and the packet formats of the subscriber service data external to the external networks. The home network is useful for distributing the digital data encoding video on demand, distance learning, videoconferencing, telephone services, Internet web pages and FTP file downloads, e-mail and other digital subscriber services to multiple devices over one or more local area networks across the entire user space. Digital data or analog signals implementing the subscriber service (subscriber service is loosely used to mean all signals, whether analog or digital, transmitted to the customer premises via an external network of some kind including a TV antenna) are transmitted to the customer premises , The gateway 14 converts the incoming signals into digital data in Ethernet packets and transmits them to the requesting devices that are coupled to the local network.
The gateway 14 functions to perform all of the physical layer interconnections and protocol conversions necessary to couple one or more local area networks running in the customer premises to digital data distribution services provided via the hybrid fiber coax (HFC) of a cable television system digital satellite data distribution network or the telephone lines of a public service telephone network. Hereinafter, these digital data delivery networks, which are external with respect to the customer premises, will be referred to as the subscription networks or the digital data delivery networks, even if some or all of them also provide analog signals as well as digital signals. For example, the cable TV subscription network becomes 16 provide analog CATV signals, in addition to the digital data carried on its upstream and downstream carriers. The satellite dish becomes similar 56 Transmission TV signals as well as digital data modulated on the downstream beam. The Public Service Telephone Network (PSTN) telephone lines 58 will also provide analog telephone signals, in addition to digital data modulated on the upstream and downstream bearers of the ADSL service.
The gateway 14 is typically a Pentium or Celeron class personal computer host with protocol conversion and switch control programs that cooperate with the operating system to control the operations of the various interface circuits, and that has one or more network interface circuits that the media of the / drive local network (s). In some embodiments, the interface circuits may be formed on the motherboard with a host microprocessor. However, in the preferred embodiment, each interface circuit is a separate expansion card that connects to the System bus of the host connects and has a suitable connector for coupling to the physical medium of the respective digital data delivery service. Similarly, the network interface to the local area network (s) may be an expansion card. However, it is desirable for the local network interface circuit to be installed in the motherboard so that it does not consume an expansion slot. In this type of module design, the circuits and software common to all the expansion modules that couple to the different subscriber networks are shared by the expansion module interface circuits. Thus, the host microprocessor, hard disk, RAM, CD-ROM / DVD, power supply, network interface circuit for the LAN (s), display and keyboard are all shared as well as the operating system, management software, and any protocol conversion software layers, all common to the network interface circuits. The gateway becomes similar 14 a packet switching process and a crossbar switch or other switching circuits controlled by the switching process to route packets received from the subscription providers to the appropriate LAN and vice versa based on the IP or other addresses in the header of the packets. These two elements can also be shared by the expansion module interface cards in the event that the sharing of switching services is required by all the subscription network interface cards in the gateway. The circuits and software specific to any particular subscription network, such as MPEG compression or decompression, tuning, detection and demodulation, carrier and clock recovery, video decoding, A / D or D / A conversion, etc., are localized the expansion module interface card associated with this subscription network.
The preferred modular design has two major advantages. First, it protects the customer's investment in the gateway by providing flexibility to couple the gateway to any subscriber network that turns out to be the most reliable, inexpensive, flexible, or easy-to-use or least cumbersome subscriber network for delivering any particular subscriber network digital data based on a service desired by the user. For example, if it turns out that ADSL is the best provider of telephone and video telephony services, but it turns out that HFC is the best provider for video-on-demand or distance learning services, and this is the only service that supports the Users interested in buying, the user can easily buy expansion modules to connect to these two subscription services. There is no need to invest in a gateway that provides hardware and software for high-speed Internet access as well as other services because the user is not interested in purchasing high-speed Internet access. The first advantage also extends to the situation where the user later changes his mind and decides that high-speed Internet access is useful, but determines that satellite delivery through DirectPC ™ is the best way to obtain this service. In such a case, the user does not need to buy a completely new gateway, but can simply buy an additional modular expansion card for coupling to a satellite dish.
second advantage of the modular design of the gateway is the property
which he has to protect the customer investment in the gateway by decoupling
the physical structure and software of the shared components
the gateway of changes
in particular the subscription networks. In the development of this
Subscription networks are likely to have physical protocols
Media, package structures, etc. are changing, which by nature
is unpredictable. Furthermore, likes over time with competitive forces that are similar
to those acting on long-distance providers of competition
the picture changes,
which subscription network is the best provider of any particular
Service is, for
the participant is interested. If ADSL is no longer the
best provider for
Phone services and the HFC network offers a better deal,
the customer does not need completely
to buy new gateway, but can simply use the ADSL interface card
remove and replace with a cable modem card to dock
to the HFC network if a cable modem card is not already present
if ADSL with strapless
Amplitude / phase modulation (CAP) paves the way for discrete multitone (DMT) modulation
As the new standard, the user can simply use the CAP-based ADSL extension module
exchange with a DMT-based module.
The structure of an embodiment of the gateway 14 will be described in more detail later. However, the genus of the gateway 14 , which is within the teaching of the invention, defined by the following properties, all of which will be shared:
a programmed host computer having an operating system and one or more protocol conversion processes and a switch control process that controls a packet switch to route packets between one or more subscriber service networks and the local network (s) to which the gateway is coupled;
one or more interface circuits for the particular local network (s) to which the packet switch is coupled to extract the packets to the physical medium of the LAN (s);
either a single interface circuit that can interface to all HFC, PSTN, and satellite digital data delivery networks that are either on the motherboard of the host or separate from the motherboard and coupled to the host system bus, or a plurality of expansion slots for coupling to individual subscriber networks Interface modules to the host system bus as desired so that each module can share the common devices of the host needed to support the module; and
wherein the common elements of the host, which can be shared by all the subscriber network interface circuits, are shared by all the subscriber networks to which the gateway is coupled, for example, such shared circuits: the host microprocessor, hard disk, RAM, CD ROM / DVD, power supply, network interface circuits for the LAN (s), display and keyboard, operating system, any management software and any protocol conversion software layers common to all the network interface circuits, and a packet switching process and a crossbar switch or circuits.
The gateway 14 will have a cable modem either on a modular expansion card or as part of the subscription network interface circuit board. This cable modem circuit may be any of the cable modems known in the art that are identified herein, or any new cable modem design that appears after this application has been filed, as the details of the cable modem are not considered to be critical at the present time The invention.
The gateway becomes similar 14 as part of its interface board or as an expansion card module, an ADSL modem (or SDSL or HDSL modem) for receiving incoming digital data modulated on a downstream bearer and outputting it as Ethernet packets on LAN (s) 18 and 20 , In some alternative embodiments, the LANs could 18 and 20 ATM LANs, or one could be ATM and the other Ethernet, or other technology such as fiber channel arbitration loop with appropriate adjustments in the gateway 14 to properly packetize the data and use appropriate circuits and protocols at all levels from the physical layer, MAC and network or routing layers up to the application layer for the particular LANs in use. ATM LAN switches and routers are available in the prior art, and the details of their construction are incorporated herein by reference.
Similarly, the ADSL modem receives Ethernet packets with digital data encoding voice, pictures, video, etc., and modulates these data onto an upstream carrier. ADSL slices the port bandwidth (the bandwidth of the twisted pair phone line from the customer premises to the central office) into multiple independent frequency channels suitable for any combination of services, including voice, ISDN, VOD programming, and interactive gaming. Downlink data rates vary from 1.544 to 6.144 Mbps with upstream rates of 16 to 640 Kbps. The gateway ADSL interface circuit will also have a voice divider if regular analog telephony is supported in addition to the LAN-connected video phones 60 and 62 or other data-consuming phones or FAX devices such as FAX 64 which receives and transmits voice and images, or call ID or other data in digital form. Such other data may include things such as background information file regarding an identified person by caller ID data transmitted by an application to the PC 22 that supports the phones. Any conventional ADSL (or SDSL or HDSL) modem design, such as the known ADSL modem manufactured by 3COM (specifically identified below and incorporated herein by reference), may be used for the PSTN ADSL interface circuit or the ADSL extension module, as the details of the ADSL interface circuit are not considered critical to the invention. The 3COM ADSL modem couples to a paired pair that carries ADSL services and has an Ethernet 10Base-T output for coupling to the LAN (s) 18 or 20 via the split packet switching circuit of the gateway.
The gateway 14 also includes a decoder box as part of its subscriber network interface board or as part of its satellite network extension module. This satellite decoder box is of the known design and suitable for transmitting digital data on a downlink to the satellite dish 56 to receive, demodulate, demultiplex, detect and decompress (if necessary). This digital data may be transmitted via a service such as direct PC or other satellite-based digital data delivery services that may become available in the future, and the interface circuitry necessary to transfer digital data transmitted to a particular personal computer via satellite. is known in the direct PC application and is hereby incorporated by reference. Typically, such satellite interface circuitry includes a tuner, a QPSK demodulator, a transport demultiplexer, and a conditional access circuit. When the satellite interface circuit is used to receive digital video signal which compresses For example, the satellite circuitry may include circuitry to decompress the digitized video data back to their original state (or near their original state when lossy compression such as MPEG was used). However, since uncompressed transmission quality standard NTSC video requires a bit rate of slightly more than 221 Mbps, whether the gateway's satellite interface circuit includes decompression circuits depends on the bandwidth of the local network (s) coupled to the gateway. If the LAN (s) are 10Base-T or 100Base-T, then the video digital data is left compressed and can be transmitted over the LAN (s) with quite acceptable quality at T1 speeds of 1.544 Mbps. MPEG compression and decompression is well known in the art and is incorporated herein by reference. MPEG compression is lossy compression which uses: a 7-tap filter to average 7 adjacent pixels or lines; Color space conversion; Scaling to a presentation resolution before digitizing; Transformations such as discrete cosine transformation, vector quantization, fractal transformation, and wavelet compression; and quantization or compaction coding to reduce the number of bits needed to represent an image pixel, such as runlength coding, Huffman coding and arithmetic coding; and interframe compression to transmit only the pixels that change between frames. Many compression standards exist, such as Px64, JPEG, MPEG 1 and 2 (MPEG 2 with transfer rates of 4 to 100 Mbps is already in use for digital video transmission via satellite services such as DirecTV) and MPEG 4 (a low-bitrate standard intended is for video phones and other small ad devices). The compression and decompression circuit of all these standards are incorporated herein by reference.
The satellite interface circuit or the satellite extension module should also be
include a conversion telephone modem for making call appearance access
to the internet about
the PSTN for
Upstream data transfers over the
Server of the Internet service provider. Downloads from the Internet
or a video server or some other digital service server
blasted up to the satellite and retransmitted on the downlink,
addressed to a specific user who requested the downlink
Has. All other decoder boxes coupled to the satellite dishes
are the same transmission
receive, reject the packets thus received because they are not addressed to them.
In the embodiment which is in 3 shown is a cable modem 12 external to the gateway, with the output IP or Ethernet packets including IP packets or ATM cells on the bus 16 for coupling to the packet switching process within the gateway. However, the preferred embodiment is as shown in FIGS 4A and 4B with the cable modem circuitry within the gateway as shown 70 , The particular cable modem that comes with 70 is labeled as DOCSIS 1.2 compatible, but it may be any known cable modem design, as it may be an external cable modem.
Referring to 4A and 4B Now, let's turn to more specific information about each of the potential subscriber service digital data delivery networks and the interface circuitry in the gateway 14 required to couple each of the external networks to the client-side LAN. The gateway 14 may be a stand-alone circuit, with all the interface circuits needed to couple to one or more external networks included as a permanent part thereof without a plug-in expansion capability in contrast to the preferred modular design disclosed in US Pat 8th where external network interface circuits can be added as needed.
First, digital data services can be delivered through a coaxial cable 10 representing the pickup line in a cable TV HFC network (not shown). The cable TV network has a head end modem (not shown) which couples the HFC cable CATV to wide area networks, such as the Internet as well as the public service telephone network (hereinafter PSTN) via one or more routers, bridges or gateways (Not shown). The head end modem can also couple the HFC to local servers, such as VOD servers.
Digital data encoding video signals, telephone services, data received from the Internet, etc. are modulated by the head end modem on one or more downstream channels for simultaneous transmission on the HFC cable system with regular analog cable TV programming. The cable TV channels each have their own frequency, so they do not conflict with each other. The downstream digital service data is modulated onto a carrier having a frequency that does not conflict with frequencies on the cable TV programming or with upstream data modulated at a different upstream carrier frequency. Data from different sources is multiplexed on both the upstream and downstream channels by any known means, including Time Division Multiplexing, Code Separation Multiplexing, Synchronous Code Division Multiplexing or Frequency Division Multiplexing.
to be delivered via the
HFC using asynchronous transfer mode (ATM) or ATM over B-ISDN type services,
which are adapted for
HFC, and the particular type of transmitters, modulation and multiplexing, which
be used. ATM and B-ISDN (Breiband-ISDN) are unstoppable
and these are a set of standards that are set
were identified by ITU-T, which exist by reference herein
are incorporated. These standards are: I.113; I.121; I.150; I.211;
I.311; I.321; I.327; I.361; I.362; I.363; I.413; I.432; I.555; and I.610.
ATM Forum Implementation Documents
of significance, which are incorporated herein by reference,
are: ATM User Network Interface (UNI) specification of PVCs; ATM Broadband Intercarrier Interface (B-UNI) Specification
and ATM Date Exchange Interface (DXI) specification; Internet engineering task force requirements for comments
(RFC), which are incorporated herein by reference, are: RFC
1483: Definition of Multiprotocol Encapsulation over AAL5; and RFC
1577: Definition of Internet IP over ATM.
is a delivery mechanism of choice, given its 48 octet payloads
and 5 octet heads
in each cell very well offer for video, image, fax, language
or data. Furthermore, the fixed cell size gives routers
and switches the benefits of predictability compared to one
Variable length frame.
These two considerations
achieve decreased delay,
when data passes through the switching system and over the transmission links in
moving small bumps.
There is no need
long frame transfer
be, the switch connections
bind and thereby cause delays
from other sources that need to use the same connectors. ATM has
also the advantage of being able to handle the amount of bandwidth required
adapt to a session during
to support the meeting. however
ATM networks neither error detection nor correction or
Protocol conversions ready. These functions are left to the user.
Data is transmitted via HFC
using discrete multi-tone (DMT) technology, typically
using in ADSL, but adapted to HFC and the particular one
Type of transmitters, modulation, multiplexing, which uses
become. DMT is a new technology developed for ADSL which
is delivered over
twisted pairs using DSPs to capture more than 6 Mbps of video,
Data, picture and speech signals over the existing ones
Pump one-pair copper wiring, but it could also be used
to data about HFC cable systems
DMT provides 4 asymmetric "A" channels
at 1.5 Mbps, each providing a VCR quality signal and which
leaving two A channels
a "sports" quality video channel
deliver and all four A channels
working together to digitally broadcast advanced resolution TV signals. DMT also supplies
a "H-zero" channel at 384 Kbps,
around Northern Telecomm's
multirate ISDN Dialable Wideband service or equivalent to deliver. This
Channel can also be used for home office telecommuters,
for high bandwidth access
on corporate LAN using Northern Telecomm's DataSPAN or others
Frame Relay services.
DMT also provides an ISDN basic rate channel, including two "B" channels of 64
Kbps and a "D" channel at 16 Kbps.
The basic rate channel allows access to a wide range of
emerging ISDN services, without the need for a dedicated
Copper pair or the cost of a dedicated NT1 unit
Home. These channels
also allow expansion of Northern Telecom's VISIT Personal Video Conferencing Services
at home at fractal T-1 rates (Px64). DMT also supplies
a signaling and control channel operating at 16 Kbps,
which gives the home user VCR type control over VOD movies
and other services including
and pause functions. Finally, DMT also offers
embedded operations or overhead channels for administration, initial
System maintenance, audits, etc. All this is delivered without interruption
the POTS service when over
a copper pair is delivered. HFC could also potentially POTS
deliver, but without a dedicated couple to each home, such
Service would be
Subject of overload
and loss of POTS for
the entire serviced neighborhood through a single cable in the
Case of a fault of the cable.
In the embodiment which is in 3 As shown, digital data on the HFC drop line is recovered by any known cable modem 12 , An example of a suitable cable modem using SCDMA upstream multiplexing is given in PCT publication WO 97/08861, published March 6, 1997, which is incorporated herein by reference. An example of software and hardware in the cable modem 12 which is DOCSIS 1.2 compatible is given in the following US patent applications, all of which are incorporated herein by reference: Serial No. 09 / 074,036, filed 5/6/98, referenced APPARATUS AND METHOD FOR SYNCHRONIZING TO SCDMA UPSTREAM OR ANY OTHER TYPE UPSTREAM TO MCNS DOWNSTREAM OR ANY OTHER TYPE DOWNSTREAM WITH A DIFFERENT CLOCK RATE THAN THE UPSTREAM; Serial No. 09 / 152,645, filed 9/14/98, referred to METHOD AND APPARATUS OF USING A BANK OF FILTERS FOR EXCISION OF NARROW BAND INTERFERENCE SIGNAL FROM CDMA SIGNAL; Serial No. 09 / 152,643, filed 9/14/98, designated TWO DIMENSIONAL INTERLEAVE PROCESS FOR CMDA TRANSMISSIONS OF ONE DIMENSIONAL TIMESLOT DATA; Serial Number 09 / 337,167, filed 9/21/99, designated MIXED DOCSIS 1.0 TDMA BURSTS WITH SCDMA TRANSMISSION ON THE SAME FREQUENCY CHANNEL; Serial No. 08 / 760,412, filed 12/4/96, designated LOWER OVERHEAD METHOD FOR DATA TRANSMISSION USING ATM AND SCDMA OVER HYBRID FIBER COAX CABLE PLANT, published as PCT Publication WO 97/34421 on September 18, 1997. PCT Publication WO 97/34421, published September 18, 1997, discusses hardware and software for transmitting IP packets received from the Internet via HFC using ATM cells and virtual channels to a remote unified cable modem and distribution of the data to peripherals over a local area network. Specifically, WO 97/34421 teaches:
Receiving Internet Protocol packets directed to an entity having an IP address on a LAN at a customer premises, and looking up an Ethernet source and destination addresses mapped to IP addresses, and generating and attaching an Ethernet header to the IP packet;
Adding RFC 1483 bits and CRC bits and sufficient pad bits to reach an integer of an ATM cell load portion of 48 bytes to result in an AAL5 format packet;
Parsing the resulting AAL5 packets into a plurality of ATM cell load sections of 48 bytes each;
Adding a standard 5-byte ATM header to each ATM cell;
Encoding the PTI field of the ATM cell header with a bit which signals which is the last cell in the packet;
Outputting the ATM cells to a formatter circuit in the headend cable modem as an OC3 TDMA stream;
Optimize ATM cell headers to reduce head size down to 2 bytes comprising the 16 least significant bits from the VPI / VCI field, and encode the last cell data into two 9th bits of the two 9-bit Sections of the downstream optimized ATM cell header;
Encoding the 9th bits of each of the first 8 "bytes" (byte is used herein in terms of a 9-bit entity);
Parse the optimized ATM downstream cells into 9-bit bytes and send them as a TDM stream to the headend cable modem downstream transmitter for transmission (this transmitter can be any conventional transmitter, but preferably it is a SCDMA transmitter, each 9-bit Byte divides into three tribits and these interleave into elements of an information vector corresponding to the virtual channels associated with the particular modem to which each 9-bit byte is directed, and spreading the spectrum of the information vector using one or more Spreading codes associated with the one or more associated virtual channels);
The headend cable modem transmitter encodes the 9-bit bytes and modulates them onto a downstream carrier for transmission via virtual channels from the headend via HFC to a remote unit (RU) cable modem.
optimized system uses a two-level addressing scheme
and a mapping between each logical channel and the associated one
this channel. The two byte header identified in the downstream optimized ATM cell
the single logical channel on which the data is to be transmitted, and this
single logic channel corresponds to a single one of the many RUs. The
Ethernet address of the specific process or peripheral device
the RU to which the payload data is addressed as soon as it reaches the
RU is included as several bytes in the payload data.
In the RU cable modem ( 12 in 3 or 70 in 4A ), the 9-bit bytes are recovered, re-ordered into AAL5 packets, and encapsulated in one or more Ethernet packets for transmission over the LAN. Specifically, the RU cable modem performs the following processing:
The incoming signals from the cable removal 10 are demodulated, demultiplexed, and recognized in accordance with whether multiplexing and modulation schemes have been used by the headend downstream transmitter for transmission on separate logic channels so as to recover the 9-bit bytes;
a formatter circuit finds the ATM cell boundaries by examining the 9th bits for the start code and reassembling the 50-byte optimized downstream ATM cell;
the formatter in each RU examines the 2-byte header in each ATM cell to determine if the ATM cell is directed to that RU and to discard the cell if it is directed to another RU (RU and Cable modem at the same customer premises), are used interchangeably) and forwards them to a segmentation and reassembly circuit (SAR) as a Utopia data stream when the cell is directed to that RU;
The SAR restores the AAL5 packet boundaries by finding the RFC 1483 bits and the last cell codes and reassembling the AAL5 packets and checking them for errors using the CRC bits and storing the corrected AAL5 packets in the memory for acquisition by an Ethernet controller and initiating one Pointer to the packet to the ethernet controller;
the Ethernet controller obtains the AAL5 packet indicated by each pointer and removes the RFC 1483 bits and sends the remaining bits as an Ethernet packet (after removing the RFC 1483 bits, the remainder is followed by an Ethernet header by an IP header followed by a payload portion).
In the embodiment of 3 when the cable modem 12 the gateway has the structure and functionality just described 14 the downstream ethernet packet on cable 16 and simply couples it to the appropriate LAN subnet through a packet switching process on the gateway (if more than one LAN is used in the customer premises). If only one LAN is used, the Ethernet packets can simply be sent to an Ethernet network interface card in the gateway for driving on the LAN. Likewise, Ethernet packets that have been received from the LAN have IP addresses that indicate that they are addressed to processes that are coupled to the wide area network to which the cable modem is attached 12 coupled through the gateway to the cable modem 12 , There they are transmitted on a downstream channel, assigned to cable modem 12 and as made by the headend modem and coupled to the Internet through a router at the headend.
Other example of high speed cable modems used for cable modem 12 can be used are given in Azzam, High Speed Cable Modems, (McGraw Hill 1997), ISBN 0-07-006417-2, which is incorporated herein by reference.
Typically, the local networks 18 and 20 10Base-T telephone lines or Cat 3, 4, or -S UTP (twisted pair) type LANs with any topology. These LANs are inexpensive, and there are many sources of low cost network adapters, hubs, and peripheres. The physical media of LAN (s) 18 and 20 may be provided as a twisted-pair telephone line with which the customer premises are already wired, or it may be a CAT-5 wiring or an RF or infrared wireless LAN system or the coax of the cable TV system which passes through the house can be used for a ThickNet (10Base-5) or ThinNet (10Base-2) LAN. The latter case assumes that the coax has been disconnected from the standard CATV drop line feed and is coupled to TV peripheral equipment only indirectly via the cable modem 12 , However, it is also possible to maintain the connection of the coaxial cable passing through the premises to the HFC cable removal 10 for delivery of FDMA analog CATV program channels to various TVs and VCRs in the home and the 10Base-T or wireless LAN for delivery of digital services to the various peripherals via network adapter circuits.
3 shows gateway 14 as paired with two LANs 18 and 20 one of which is a high-speed LAN and the other is a low-speed LAN. The high-speed LAN can be a 100BaseT and is used to deliver high-bandwidth consuming services such as video conferencing, video-on-demand, high-speed Internet access. There may be one or more LANs coupled to the gateway. If there is more than one LAN, the gateway will stop 14 also a routing function ready to put the Ethernet packets on the appropriate network to which the peripherals are coupled that have the IP address in the packet.
The local networks 18 and 20 also serve the dual purpose of allowing the computers on the network to communicate with each other and share resources, such as shared hard drives, printers, etc. For example, the PC 22 typically a windows-based personal computer, but may also be a Macintosh or other workstation connected to network computers 24 and 26 can communicate to allow files on the hard drive from the PC 22 to be generated, which can be accessed by the network computer, or to generate documents on the network computers 24 and 26 that on the hard disk of PC 22 are stored. Through the gateway 14 and an internal ADSL modem or cable modem, the network computers can also access the Internet and download web pages, send e-mails, and so on.
The television 28 is linked to the local network 18 via a network adapter 30 which functions to convert compressed digital data in received Ethernet packets into video signals on line 32 , The TV can be used in interactive communications so that upstream data can be sent using an infrared or RF wireless keyboard 34 , Such data may include the title or number of a VOD movie to be requested or upstream text to be sent in a multimedia-interactive presentation. In addition, an infrared or RF remote control 80 used to transfer commands to the Network Adapters 30 such as play, pause, slow motion, stop, rewind etc. to control video-on-demand services. Information that the customer wishes to send is entered on the keyboard and communicates with the network adapter 30 via infrared or RF transmission from the keyboard 34 and / or remote control 80 , The data transmissions are received, demodulated and recognized to recover the data, and the data is addressed and packetized into IP packets encapsulated within Ethernet packets by an infrared and / or RF receiver 82 in the network adapter 30 (please refer 5 , which is a block diagram of the network adapter 30 is). The Ethernet packets containing the upstream VOD request data are to the gateway 14 addressed. These packages are on the LAN 20 passed through a network interface card 84 which performs media access control and physical layer protocols, whether LAN is in use, such as CSMA / CD in the case of Ethernet LANs.
The IP packet encapsulating each VOD request is addressed to the particular video server that will provide the data. Standard mouse or touchpad type technology in the infrared keyboard and / or remote control 80 sends pointer information to the receiver 82 so that the user can request menus from any video server and can point to a video selection from any menu displayed on the TV. In one embodiment, the remote control has 80 or IR keyboard 34 Soft keys that can be pressed to request menus of VOD selections from the satellite, HFC and ADSL video servers. When these function buttons are pressed, the receiver converts 82 the request in an IP packet addressed to the appropriate video server, requesting transmission of the current menu data. The menu data listing currently available selections are sent as downstream IP packets addressed to the video adapter having the IP address that was the source address of the menu request packet. These IP packets reach the IP video circuit 242 where they are recognized and directed by bus 87 to the 2/3-D graphics circuit 83 The data is converted into graphics data signals on line 85 which will be used to display the menus.
When the user points to a particular menu selection on a displayed menu, the pointer information is transmitted to the receiver 82 and converted to graphics instructions that are transmitted over the line 81 to the optional 2/3-D graphics circuit 83 , The graphics circuit 83 generates graphics for superimposition on the TV display, and the pointer information is converted into a graphic image such as a pointer or a hand that the user can move on the displayed menu by using a mouse or a touchpad. When the user points to a VOD selection and issues a "Request" command, the menu in which the pointer is located is transmitted over the bus 81 to the receiver 82 , and the position on the menu where the pointer is currently located is determined by the graphics circuit 83 and transmit to the receiver 82 , The menu, and thus certain current location data, are mapped to an IP address of a particular server and a particular VOD selection that is available from that server. The receiver 82 then uses the IP address of the video server as a destination address and its own IP address as a source address and the requested selection to generate an IP packet carrying the VOD request. This packet is then encapsulated in an Ethernet packet addressed to Gateway 14 and sent to the gateway via the NIC 84 and the LAN 20 , The gateway removes the Ethernet header and routes the IP packet to the appropriate video server through the appropriate upstream medium for that video server.
In alternative embodiments, the user may simply enter the number of a category of video from a displayed menu of available categories and the number of video selections on the displayed menu. The menu number and program number are then converted into a VOD request IP packet by the receiver 82 and then encapsulated in an Ethernet packet addressed to the gateway 14 , The gateway 14 then processes the VOD request as described above.
If the upstream VOD request packet is the gateway 14 reached, it is processed by the Ethernet (or other LAN protocols) to IP protocol conversion, and routing process (hereinafter referred to as routing circuit) is executed by the host computer circuit and the software processing symbolized by block 86 in 4A ( 4A - 4B together are a block diagram of one embodiment of the gateway). The routing circuit 86 then routes the VOD request packet to the appropriate subscription service data delivery network for delivery to the processing / target device named in the IP destination address.
The routing circuit 86 is as a separate logic block in 4A shown by the host microprocessor 128 and its associated peripherals: Random Access Memory 129 , non-volatile memory 131 to save the bios, hard disk controllers 133 and the hard drive 135 he controls display adapters 137 and display 139 , Keyboard interface 141 and keyboard 143 , All these peri phergeräte are conventional. In an actual circuit is the routing circuit 86 usually the host microprocessor programmed to perform the IP to Ethernet and conversely protocol conversion, execute routing table construction and packet routing functions along with any other necessary functions for a router including network interfaces and any other functions required for the routing Process described in the flowchart herein. Description of Gateways, Routers, Internet Protocol and IEEE 802.3 Ethernet Local Area Networks can be found in Tannenbaum, Computer Networks, 2nd Ed. (Prentice Hall 1989) ISBN 0-13-162959-X and Stallings, Data and Computer Communications, 4 Ed., (MacMillan Publishing 1994) ISBN-0-02-415441-5, both of which are incorporated herein by reference.
The function of the gateway is to provide protocol conversion, packet format conversion, video, voice and data demodulation, recognition and demultiplexing services, conventional access control to prevent non-subscribers from receiving services that they have not subscribed to. The gateway 14 performs functions of a cable modem and a set-top decoder box for a satellite digital subscriber service, such as DirectPC, and performs functions from an ADSL modem. As part of this interface circuit, the gateway performs MPEG encoding services, IP video. IP video involves the process of retrieving downstream IP packets and sending them to an input port of a router process and receiving Ethernet upstream packets and converting them into IP packets and upstream transmissions thereof. The gateway also performs IP telephony services (similar to IP video services, with the exception of telephony over the Internet) as well as switching and routing services. More details about the structure and operation of the gateway will be included below.
It handles the network interface cards of the peripherals, the Ethernet packets from the LAN 18 to determine whether they are directed to the Ethernet address of this peripheral device, to convert the payload data into a usable format for the peripheral device and to transfer the data to the process having the IP address in the packet.
Assuming that the service is being carried by the home network, bidirectional data transmission is needed and ATM is used upstream, with the upstream data transfer processing from the peripheral to the internet via the cable modem 12 as follows, it is assumed that the cable modem is of the type defined in PCT Publication WO 97/34421, which is incorporated herein by reference:
The login process, which must send upstream data, places one or more Ethernet packets on the LAN 18 which include the entity's IP address on the Internet to which the data is directed;
Each Ethernet packet is routed through the gateway 14 to the cable modem 12 if it has an IP address indicating that it is addressed to an entity on the Internet to which the gateway is coupled via the cable modem 12 ;
the SAR in the RU cable modem adds pad bits to each Ethernet packet, calculates CRC-32 error detection bits, and adds RFC 1483 bits so that the resulting packet has a multiple, integer value of 48 bytes;
the SAR parses the packets into multiple 48 byte ATM cell payload sections without header bytes, adds default 5 byte ATM cell headers to each payload section using a virtual connection identifier identifying the upstream virtual channel assigned to that RU to construct the VPI / VCI field, and uses last cell, normal cell and idle cell information to construct the PTI field, and calculates an HEC field and transmits the resulting ATM cells to a formatter a Utopia stream;
the formatter adds a 9th bit to each byte in the cell and encodes the 9th bits with a start code, last cell, normal cell and idle cell codes using the information in the PTI field of each ATM cell header;
the formatter removes the 5-byte header from each ATM cell while storing the information, and parses each upstream ATM cell into 9-bit bytes and places a 9-bit byte in each time slot of an upstream information vector corresponds to the virtual channel assigned to this RU modem and transmits the information vector to the upstream transmitter in the RU cable modem 12 using the information in the VPI / VCI field of the header to identify which virtual channel is to be transmitted in which respective 9-bit byte of each ATM cell;
the upstream transmitter of the RU modem transmits the upstream data in the appropriate virtual channel such as by spreading the spectrum of the 9-bit byte using one or more spreading codes associated with the virtual channel (s) assigned to the RU;
the spread spectrum data is then transmitted on the upstream carrier;
the receiver in the headend cable modem receives the upstream transmissions from each RU and demodulates and demultiplexes and detects the transmitted data from each 9-bit byte and places it the recovered 9-bit bytes into the time slots on a TDMA bus corresponding to the logical channel in which the data was received;
a formatting process in the headend modem demultiplexes the TDMA stream and reassembles the 48-byte optimized upstream ATM cells using the signaling data in the 9th bits and places each ATM cell in a part of a cell buffer dedicated to Storing ATM cells from the RU that generated the data using the timeslot data to determine from which RU each ATM cell arrived;
a cell output control process then receives each 48-byte ATM cell and generates a standard 5-byte header and transmits the standard 53-byte ATM cell in the OC3 format data stream to a segmentation and reassembly circuit in a router Kopfendkabelmodem;
the SAR error checks the 53-byte ATM cell using the HEC field and removes the header bytes while preserving the VPI / VCI and PTI field information, and reconstructs the AAL5 sequence using the RFC 1483 bits and the last cell data encoded in the PTI field to find the packet boundaries and connecting the 48-byte payload portions of the ATM cells and checking the packet for errors using CRC bits ;
if no errors are found, the RFC 1483 bits and the CRC bits and pad bits are removed to leave an Ethernet packet header, an IP header, and a payload portion, and the result is sent to a router for routing the appropriate subnet to get to the destination that has the IP address somewhere on the wide area network.
If the cable modem 12 With the architecture of any of the cable modems described in Azzam, High Speed Cable Modems, suitable modifications can be made to the above-described downstream and upstream processes described above, or the upstream and downstream processes therein Modems used can be used for delivery of the same digital services that they have used in the prior art for delivery. For example, any cable modem hardware and software structures known in the art used in actual field trials identified in Azzam, High Speed Cable Modems, Chapter 14, Section 14.2, pages 512-518 (McGraw Hill 1997), ISBN 0-07-006417-2 can be used, and all of these modem designs are hereby incorporated by reference. The cable modems whose circuitry and software are incorporated herein by reference include: LANcity personnel; Hybrid Networks Cable Client Modem 211; Zenith HomeWorks Elite; Motorola CyberSurfr; General Instruments SURFboard SB1000; Hewlett-Packard QuickBurst; Com21 ComPort; Toshiba and any other cable modem that complies with the IEEE 802.14 standard.
Typically, the IEEE 802.14 compliant cable modem class will include types that have the following characteristics:
Downstream data included in one of the 6 MHz TV channels occupying the spectrum above 550 MHz;
Upstream channel, with an associated band between 5 and 45 MHz;
64-QAM downstream modulation delivery above 30 Mbps data rate;
Upstream channel having QPSK modulation or a combination of TDMA and synchronous code division multiple access multiplexing techniques and QAM modulation delivery of 2 to 10 Mbps in each upstream channel;
a media access control software layer for communicating upstream access between multiple users sharing the same cable medium;
a MAC protocol that is ATM-friendly using the ATM cell transport concept and possibly including segmentation of ATM cells into small segments to improve system performance;
Status and control information loopback from the upstream to the downstream to provide remote cable modems with status and control information to determine a pecking order;
the upstream channel, divided into frequency channels assigned to individual users, or a combination of two multiplexing methods, such as TDMA and synchronous CDMA or CDMA.
close within this genus
Circuits and software to achieve time synchronization
where frame alignment for
appropriate demultiplexing is necessary.
if not necessarily within the genus, close the
better modems in the genus also time synchronization coupled with
TDMA and CDMA to reduce intersymbol interference, such as
also performance alignment and adaptive equalization to other shapes
from interference. These are better cable modems
such as. pseudorandom
Nesting or DES encryption
and a MAC layer protocol, the fairness in upstream bandwidth access
These cable modems have been used to provide resident online subscribers services that include Internet access e-mail, world news, shopping, local content including city government, schools, libraries and other community news, multimedia services, campus networks, distance education and telemedicine, internet access to schools, Prodigy, Jones Internet Channel and home work programs.
Details of gateway interfaces
to downstream cables,
Satellite and ADSL.
Referring to 4 there is shown a block diagram of one embodiment of the gateway 14 which is configured as a stand alone circuit where interfaces to the satellite, HFC and PSTN networks are all implemented on the board. This circuit may be an expansion card in a personal computer or it may be integrated into the motherboard of a personal computer. The other known components of the personal computer are not included in the interest of simplicity 4 shown, but it is sufficient to say that the host CPU of the PC is coupled to the circuit in 4 is shown by the address, data and control buses of the PC, so that the circuits that need control inputs or data from the host CPU can receive them. The control and data inputs needed by each circuit will be described as the circuit is described.
The embodiment of the gateway 14 who in 4 shown completes the entire circuit of a DOCSIS 1.2 cable modem 70 in it. First, consider the interface circuitry to couple the HFC to the LAN, the HFC line 10 is coupled to an upstream and downstream combiner and isolation circuit 90 , There are upstream modulated RF carrier signals on line 92 from upstream isolation amplifiers or couplers 94 coupled to the cable 10 , and downstream-modulated RF signals are received from the cable 10 and placed on wire 96 , Typically, combiners 90 include a bandpass filter to prevent upstream RF signals from entering the line 96 and, optionally, a degree for the line 92 include to prevent reflections. The isolation circuit 98 Typically a buffer amplifier or capacitance or other circuit such as a surge arrester protects the internal circuitry of the gateway from any unwanted DC signals or lightning strikes on the HFC.
In the embodiment which is in 4 shown are three tuners 100 . 102 and 104 used. The tuner 100 is tuned to any of the conventional CATV analog video channels in NTSC, PAL or SECAM format. Typically, the overall bandwidth of the HFC will be split into different frequency bands for CATV FDMA analog video channels, an upstream DOCSIS data management and control signal band, a digital VOD signal band, and a downstream DOCSIS data band. The frequency band for upstream data and management and control signals extends from 0 to about 50 MHz. Within this band, upstream DOCSIS data will be modulated onto a carrier frequency, and management and control data will be modulated to a different carrier frequency. There may be multiple upstream management and control channels at different frequencies or at different timeslots or at the same frequency with the data from each management and control channel that has spread its spectrum with a different spreading code. Typically, the frequency band from 50 to 500 MHz will be reserved for FDMA 6 MHz wide analog CATV video signals. Digital video data, such as for VOD or teleconferencing, etc., is typically modulated onto a plurality of different frequency channels in a band above 5 MHz, each channel being about 6 MHz wide, and includes a plurality of video, audio and associated data sub-channels separated by TDMA. Downstream DOCSIS data, such as web pages downloaded during high-speed Internet access, are typically modulated onto a carrier having a frequency somewhere above the video-on-demand carrier frequencies.
One of the functions of the gateway 14 Its purpose is to deliver requested services to all the peripherals in the customer premises seamlessly over the shared LAN, thereby eliminating the need for separate coaxial cable wiring to provide CATV analog signals, a digital network to deliver digital data, telephone wiring to provide conventional telephone service. All of these services are delivered via a single digital data distribution system that includes one or more LANs. To this end, even CATV signals, which are analog when delivered, are digitized, compressed, converted into IP packets and then into Ethernet packets and transmitted to the different televisions over a LAN.
Distribution of analog CATV signals
The tuner 100 Starts this process by receiving control data from the microprocessor 128 defining the CATV analog video channel that has been requested. Users request CATV analog transmission channels via their IR keyboards 34 or remote controls 80 in 3 , These requirements are encapsulated in management and control Ethernet packets sent to the host CPU 128 through network adapters 30 are addressed. The host CPU receives them and creates a bus packet on bus 156 that is addressed to the tuner 100 which tells him to tune to which channel. The host bus 156 can be a PCI bus in a Windows-based personal computer, but heavy traffic can bring such a bus to its knees, since only two devices can use that bus to communicate at a given time. In alternative embodiments, a high capacity multiplexed bus, such as a standard H.100 TDMA bus coupled by appropriate bus drivers to the host bus, may be used in a computer with sufficient expansion slots for all the necessary expansion modules to implement a flexible gateway. In other words, in low bandwidth consumption embodiments where only one or two of the expansion modules included in 8th A Windows-based personal computer with a PCI or ISA bus and one or two expansion bays may be sufficient. However, in high bandwidth consumption embodiments, where many or all of the expansion modules included in 8th are shown, are present or perhaps added, as the number of services and external networks that are to be used grows, the gateway can 14 the configuration have one or more personal computers, each equipped with a fast microprocessor and a PCI or a somewhat faster bus, one or more of which process the software symbolized by 8th to split up the work. These servers would be coupled to the LANs through one or more NICs with their one or more host busses coupled to other expansion module interface boards through one or more high-capacity buses such as a H.100 TDMA bus, a Firewire, or even FDDI. or Fiber Channel Arbitrated Loop LAN technology. The expansion module interface board would have a plurality of expansion bays connected to the high capacity bus (s) or LAN (s) which couples the expansion module interface board to one or more servers. Each expansion bay would be available to one of the expansion modules, which in 8th are shown to couple to the shared software and hardware facilities of the servers. For ease of explanation, all of these various alternative bus or LAN type connections between the server (s) and the modules in the expansion slots will be referred to simply as the host bus or the PCI bus 156 , There will also be descriptions of circuits having the effect of placing data in PCI bus or host bus packets that are addressed to a particular circuit to which they are to be sent, such as the IP video circuit 158 or the routing process 86 , This is to be understood as actually placing the data in a packet having a destination address set to the target circuit or the host bus's process control, and writing the address of the destination circuit to its control line and placing the data to be transferred on the data lines and activating respective necessary control signals to latch the address and clocking the data into a data register or other memory.
The RF output of the tuner 100 on the bus 134 is then digitized by an analog-to-digital converter in the A / D matrix 130 , The digital samples on the line 136 are input to a video demodulator 138 operating in the digital domain to demodulate the digitized analog video signal by removing the RF component. The video demodulator 138 gives digital data to the line 166 which represent a conventional baseband NTSC, PAL, or SECAM format video signal.
The digital data on the line 166 have too high a bitrate for transmission over the LAN because uncompressed video transmission is at 221 Mbps. There, the video data must be compressed. MPEG-II compression is preferred, but any other known form of compression that is currently known or that will be developed in the future will be appropriate because the shape of the compression is not critical. MPEG-II compression circuitry is well known and is used for the MPEG coder 146 , However, MPEG-II compression does not compress NTSC, PAL, or SECAM format signals. They must first be converted to YUV format luminescence and chrominance signals. This conversion is done in the video decoder 142 which is of a known type of circuit in any video system using MPEG II compression.
The compressed video data is encapsulated in PCI (or other types) bus packets that are addressed to the IP video circuit 158 , There, the compressed video data is encapsulated in IP packets addressed to the network adapter of the TV where the CATV video channel is to be viewed. The IP video circuit 158 determines which IP destination address to use in constructing the IP packets over data sent by the host microprocessor 128 were received. When the original request is received, the host microprocessor determines 128 also in addition to notifying the tuner 100 to which channel he should tune, from the Ethernet packet source address, which TV network adapter the Da requested. The IP address of this network adapter is encapsulated in a PCI bus packet and transmitted over the host bus 156 to the IP video circuit. The IP packets encapsulating the digitized CATV channel are then sent over the bus 160 to the routing process 86 ,
The routing process 86 is a conventional IP to Ethernet routing process that examines the IP packet destination addresses and looks up the corresponding Ethernet addresses. The IP packets are then encapsulated in Ethernet packets and routed to the appropriate LAN network interface card for LAN 18 or 20 depending on the Ethernet destination address of each packet. Conversely, the process works for incoming Ethernet packets from the LAN (s).
When the IP packets reach the network adapter of the TV that has ordered the CATV channel, they are converted into a video signal that can be displayed by the TV, through the circuit described below in connection with the discussion of 5 ,
Disadvantage of viewing CATV transmission channels is
that there is no facility to have VCR-like controls
like pause, rewind,
Play, slow motion or stop over
the incoming video. This is one reason why VOD is more advantageous
is. Let's turn to an overview discussion of VOD delivery via cable modem.
will VOD delivery via ADSL modem
or satellite dish
be discussed. The discussions
herein regarding delivery
VOD also refer to delivery of videoconferencing services,
Home shopping, distance learning and other multimedia services, the video,
Include images or other multimedia data. There are also there
in the functioning and structure of the circuit for receiving,
Record and distribute digital VOD via satellite, therefore
There will apparently be a few repetitions of discussions that follow.
First a quick overview.
VOD downstream frequency band
has a plurality of video channels
on, each at a different carrier frequency. Each video channel carries several
MPEG-II compressed video with its associated audio and sometimes with
one or more additional TDMA subchannels, the
The tuner 102 is commanded by the host microprocessor 128 to tune to a particular VOD channel. the customer will request a specific VOD program using the IR keyboard 34 or remote control 80 , The microprocessor 128 receives the request information about management and control Ethernet packets generated by the network adapter 30 and be driven on the LAN 20 , As an example of how the video, audio, and associated data subchannels of a VOD program are used, assume that the tuner 102 is tuned to a home shopping VOD channel where a plurality of customers wish to purchase an item shown by the video data on a first subchannel and described on an associated audio sub data channel, there may be many customers there who want to buy the item who need to talk to an operator. These many customers have digitized their phone calls into IP packets on digital phones, such as 62 in 1 , with each packet addressed to the IP address corresponding to the phone number shown on the display. These packets are encapsulated in Ethernet packets and transmitted to the LAN 18 or 20 to the gateway 14 , There they are received through the circuit process 86 and the Ethernet heads are removed, and the IP packets are sent to DOCSIS modem for transmission to an upstream channel.
the headend modem restores the IP phone packets
and routed to the IP address where the operators are waiting. It is assumed
that three callers call to the item shown and described
to buy. The language of the three different operators, the
These calls are digitized into IP packets that are addressed
are to the digital phone that is being used by the caller,
they talk to. These IP packets that are addressed to the
Phones of the three different callers are QAM-modulated by the
Headend modem modulator that transmits the VOD program and transmits downstream
as allocated data on three different TDMA subchannels, the
associated with the video and audio sub-channels of the home shopping presentation.
The host microprocessor 128 says the tuner 102 to which channel it has to tune in the VOD band, via control data being transmitted via the data, address and control bus 156 (also referred to as the host bus). The RF tuner 102 tune to the channel and reject all other signals.
Then the video, audio and associated values for each video, audio and data QAM modulated constellation point are recovered by the QAM demodulator 146 ,
The recovered data values become then split by the transport demultiplexer 148 in video, audio and associated data streams on lines 150 . 152 and 154 , The transport demultiplexer receives control data from the host microprocessor via data, address and control buses 156 which tell him which subchannels are to be singled out in the demultiplexing process.
A conventional conditional access circuit 126 then decrypts the recovered data to prevent any unauthorized access to it. The decryption process may be the same process currently used in Ku-band satellite digital video delivery or any other conventional encryption process. Since VOD subchannels are only sent to certain users, the data can be encrypted by PGP using the public key of the user to whom the data is directed. The user then uses his private key to decrypt the data.
The conditional access circuit includes a conventional PCI or other bus interface circuit. Typically, the gateway is implemented as one or more boards on a personal computer such as a Pentium class or PowerPC Macintosh, which has a system bus. Any system bus that is fast enough to carry the system load bit rate in the worst case may be sufficient. The worst case of system load is based on the number of types of peripherals in the house. Typically, a compressed digital video channel can be provided with good picture quality at 2 Mbps, so that if a household has 4 TVs, all switched to different VOD channels, and a videoconference takes place, 10 Mbps should be adequate. PCI buses have maximum bit rates well over 10 Mbps, making a PCI bus for system bus 156 is adequate for most applications. The conditional access circuit bus interface packages the decrypted video, audio, and associated data into PCI bus packets that are addressed to an IP video circuit 158 , and places it on the bus 156 over the line 160 ,
The IP video circuit receives the PCI bus packets and encapsulates the video and audio data into IP packets addressed to the network adapter 30 who requested the VOD program. The associated data is encapsulated in IP packets addressed to telephones 62 (or no matter which phone is used to talk to the operator). The IP packets are then transmitted over the line 160 to the routing process 86 ,
The routing process 86 is a conventional IP to Ethernet routing process that examines the IP packet destination addresses and looks up the corresponding Ethernet addresses. The IP packets are then encapsulated in Ethernet packets and routed to the appropriate LAN network interface card to LAN 18 or 20 depending on the Ethernet destination address of each packet. Conversely, the process works for incoming Ethernet packets from the LAN (s).
will we turn to a more detailed discussion of the process,
which is executed
through the system to VOD about
to receive either satellite, HFC or ADSL.
6A - 6C together comprise a flow chart of a preferred embodiment of the processing occurring in the system to request a VOD selection via either HFC, satellite or ADSL modem. Referring to together 4A and 4B . 5 and 6A - 6E , a user requests a specific video program via the IR keyboard 34 or remote control 80 acting as a pointer device to on the TV 28 in 3 to point to a displayed menu selection. The selection is received by the IR or RF receiver 82 in 5 as symbolized by step 106 in 6A , The video selection along with the IP address of the network adapter 30 is encapsulated in an IP packet and then encapsulated in an Ethernet packet through the network adapter 30 and started on LAN 20 (Step 108 ). The IP packet has the IP address of the network adapter 30 as its source address and the IP address of the VOD server as its destination address. The IP address will usually be different depending on whether the video selection was requested via HFC, Satellite or ADSL, as each network probably has its own video server. The user usually selects the VOD selection from a displayed menu on his display for each network, so by displaying on the desired selection on the menu of the ADSL network, for example, the IP address is set to the IP address of the video server for the ADSL -Network.
The network adapter encapsulates the IP packet requesting video selection into an Ethernet packet (step 108 ). The Ethernet destination address is the routing process 86 in the gateway. The IP packet payload message identifies the movie or other desired video program, and in some embodiments identifies the particular VOD channel and subchannel to which the Gateway VOD tuner is tuned (step 108 ). MPEG-II compressed video is transmitted on two or more sub-channels (one video, one associated data, and zero or more associated video sub-channels), and this is done regardless of whether the delivery medium is HFC, satellite or ADSL. step 108 represents the preferred process wherein the head end of the HFC, satellite network or ADSL center observes the channels and subchannels for load and sends downstream load, balancing messages indicating which channels and subchannels are free. These load balancing messages are monitored by the gateways, and the channels and subchannels that are available are selected by the gateways for "storage," thereby helping to balance the load across the network, however, in other embodiments, the video server and / or headend Simply place the requested video selection on any unused subchannel of a channel that is not fully occupied, and send a downstream management and control message to the gateway that originated the request, indicating where the requested video selection will be found. microprocessor 128 in the gateway then sends data to its circuit to cause it to tune to the correct channel and to demultiplex the correct subchannels. The "subchannel" means the particular time slots or spreading codes to be used in receiving the video data when tuned to the frequency of the "channel". In embodiments where only one video sub-channel is carried per channel, then sub-channel and channel mean the same thing.
the preferred embodiment
indicates the headend modem (or other headend circuit such as
e.g. the uplink transmission center in
the case of satellites or the ADSL center - hereinafter
these other headend circuits will be referred to as headend modems for brevity)
a plurality of VOD modulators / transmitters (hereinafter
Called modulators), each of which is coupled to the VOD server
and each of which contains a plurality of streams of MPEG-II compressed
Receives video data.
Each modulator is structured to transmit a downstream VOD channel
with a plurality of MPEG-II compressed video / audio / linked data streams, the
therein are multiplexed by TDMA, CDMA or synchronous CDMA.
to implement the preferred form of load balancing observed
the headend modem, which subchannels from each downstream VOD channel
be used. It then transmits
Management and control messages to all gateways via the
HFC, subscribers' satellite downlink or ADSL lines, indicating
which VOD channels
and which upstream channels are the gateways
should use to send messages indicating that
a gateway has "stored" on a particular
Channel or subchannel.
The meaning of the term "stored" or "stored" is as follows. The gateways receive these transfer load balancing messages, and the host CPU of each gateway with a pending VOD request commands its VOD tuners (such as tuners 102 or 180 or a corresponding tuner in the ADSL modem 182 in 4A ) to tune to a channel that is an available subchannel as symbolized in step 108 , The host CPU then commands the appropriate transport demultiplexer (eg, demultiplexer 114 for HFC delivery or demultiplexer 184 in the case of satellite or a similar but not shown demultiplexer in the ADSL modem 182 ) and to select only the compressed video and audio sub-channels bearing the requested program, as well as the associated data sub-channels. "Storing" or "Storing" therefore means tuning the appropriate digital VOD tuner and transport demultiplexer in the gateway to a particular channel and subchannel.
The channel and subchannel storage information is included in the gateway in the IP packet carrying the upstream video request or is contained within a separate IP packet generated by the gateway relating to the IP packet which carrying the VOD request, also symbolized by step 108 , This storage data helps the video server or router in the headend modem (or equivalent circuit in a satellite or ADSL VOD network) to bring the requested video data to the correct modulator transmitting on the VOD channel to which the gateway is coupled , to the requested IP address to which is tuned. The channel and subchannel data contained in the upstream message are also used to control the modulator to place the video and associated audio data on the subchannel to which the gateway is tuned.
Continuing with the discussion of 6A , the Ethernet packet is received by the switching process 86 (after passing through the network adapter card of the host computer and up through the Ethernet protocol layers, where the ethernet head is removed as symbolized by step 110 ). The switching process looks up the destination address of the IP packet in a lookup table and determines from the destination IP packet address that it is directed to a VOD server coupled to the headend modem, driving HFC 10 or the headend driving the uplink to the satellite or the ADSL center (step 112 ).
step 116 represents the general purpose of transmitting the IP packet containing the VOD program request to the appropriate video server via the appropriate transmission transfer medium. The following paragraphs discuss the different cases individually, and step 116 is to be interpreted as covering each of these individual cases, depending on which video service is addressed by the IP packet. The following discussion assumes that the gateway is equipped with HFC, satellite, and ADSL expansion modules so that VOD can be requested from any of these three networks. However, the gateway may also have only any subcombination of one or more of the HFC, satellite, or ADSL modem expansion cards, so step 116 only represents routes of the IP request packet to a video server or possibly a selected one of two different video servers providing VOD over two different networks.
In the case of an IP request packet addressed to a video server connected to the HFC 10 is coupled via the headend modem to provide a VOD selection over the HFC, represents step 116 the following subprocess. The IP packet is routed to DOCSIS modem 70 and transmit on an upstream management and control channel. In the preferred embodiment, the management and control channel used to transmit the upstream request is the channel designated in a downstream load balancing message from the headend modem, indicating which channels and subchannels are available and which upstream channels the gateways are to use Show that they have stored on one of the available channels and subchannels. The IP packet is recovered from the HFC and directly coupled or over the Internet to the video server to which it is addressed. The video server may be directly coupled to the headend modem or indirectly over the Internet, in which case the IP request packet is sent through the router at the headend over the Internet to the video server.
In the case of an IP request packet addressed to a video server coupled to a satellite uplink head-end circuit, the upstream channel is beyond the PSTN, so step 116 represents the following. The IP packet is routed to the ADSL modem 182 or the DOCSIS modem 70 for upstream transmission over the telephone lines. When it is routed to the ADSL modem, it transmits the IP packet request message upstream over the PSTN lines to the ADSL center where it is routed to the video server coupled to the satellite uplink via a connection to the Internet at the CO or a setup connection via the PSTN directly to the video server.
the IP packet addressed to a video server that delivers VOD over the
Satellite network routed to the DOCSIS modem, that will
IP packet transmitted via the
HFC to the headend DOCFSIS modem. There the package is restored
and reassembled (if necessary) and sent to the router
for delivery over
the Internet or other WAN to the video server to which the package
is addressed. Alternatively, the head-end DOCSIS modem can establish a connection
Use the PSTN to the video server or IP telephony to deliver the
Packets to the video server via
the internet over
IP telephony circuit that is linked to the Internet at the
If the IP-VOD request packet is addressed to a video server delivering via ADSL, step represents 116 the following. The routing process 86 routes the IP packet to the ADSL modem 182 where it is transmitted over the ADSL upstream channel to the ADSL modem at the CO. The CO then routes the IP-VOD request packet to the video server directly coupled to the CO, or gives it to a router connected to the Internet for routing to a video server coupled to the CO over the Internet (the term Internet means the Internet or any other wide area network that exists today or that will exist in the future). Alternatively, the CO may establish a connection to the video server via the PSTN and send an IP-VOD request packet over the set-up connection or may communicate with another CO where a video server is located by a T1 line or DS1 or other high-speed telephone lines. The processing and circuitry of video-on-demand ADSL delivery taught in U.S. Patent 5,247,347 may be used, and this patent is incorporated herein by reference.
The step 120 represents the optional step of authentication and / or conditional access performed at the headend prior to routing the IP request packet to the video server. In some embodiments, the IP packet carrying the VOD request is only routed to the video server if the user making the request is authenticated and / or a subscriber authorized to the requested service. This is typically done by using the source address as the search key to search a lookup table from authorized users. The way in which the requested services such as the VOD are watched so that they are only delivered to authorized subscribers is not critical to the invention, and the look-up function as part of step 120 can be replaced by any known manner of blocking services only for authorized users. The lock function can also be performed on the gateways after transmission of the VOD data downstream, and the gateway 14 has conditional access modules 126 and 186 which represent these embodiments. In these embodiments where the conditional access lock function is performed on the gateway, step 120 not required. Processes for performing conditional access blocking at customer premises are well known in C-band and Ku-band subscription-based analog-and-digital video transmission and need not be described here. In order to implement this type of conditional access at the customer premises, each gateway has a decryption module ( 126 . 186 and similar circuit in ADSL modem 182 ) with a key or password stored therein. This key or password is used by the video server or other service providers to encrypt the VOD data or other data that encodes the requested service using the authorizing subscriber's public key. Only this subscriber can decrypt the data using his private key. The conditional access modules 126 and 186 in 4A are intended to symbolize any of these known prior art structures and processes for blocking access by unauthorized persons to services.
After the IP packet reaches the video server, it reads the IP packet and opens the file, saving the data of the requested movie or other video production (step 124 ). The video server then begins to transmit the video data as IP packets addressed to the TV and the network adapter 30 who requested the movie (step 124 ). The IP packets typically include compressed video data through MPEG-II compression. The step 124 is intended to describe one of the following three subprocesses of delivery of video data carrying IP packets depending on the video server to which the original IP packet carrying the VOD request was addressed and whether the IP video data packets can be delivered via HFC, via satellite or via a DSL connection. The step 124 is not intended to represent delivery of VOD data through all three networks. The discussion of each sub-process is marked by a header, and three different lines of steps are shown in FIG 6A - 6E for the three different delivery networks, as each delivery network is coupled to a different circuit in the gateway 14 ,
First, in the case of HFC delivery, the step represents 124 the process of transmitting the IP VOD packets to the modulator in the headend modem which transmits downstream on the channel identified in the original request packet. Transmission to this modulator may be through a local direct connection or over the Internet or other WAN or through a T1 or DS2 leased line or possibly through other high speed PSTN connection such as DSL.
Video data is compressed and in some known manner
before the transfer.
The preferred way of implementing conditional access is
to perform the lock functions on the video end of the connection,
to avoid downstream bandwidth too
waste by requests from unauthorized users.
In the HFC delivery case, the compressed video and audio data (and possibly associated data such as IP telephony packets) are transmitted by the headend on the channel and subchannels identified in the stock data given in the origin request message and arrive , the gateway 14 on over the line 10 (Step 136 ). In alternative embodiments, the video server and headend will cooperate to place the VOD data on unused subchannels of a channel that is not fully utilized, and send a downstream management and control message indicating the gateway where it will receive the requested VOD. Program can find (step 136 ).
After reaching the gateway on the HFC connection 10 the RF downstream signal is coupled via the coupler 90 to the buffer / isolation circuit 98 and reaches the tuners 100 . 102 and 104 , The tuners 100 and 104 reject it because they were not instructed by the host CPU 128 of the gateway to listen for analog video data or DOCSIS disk frequencies. The tuner 102 however, has been instructed by the host microprocessor 128 (hereinafter the "host") to tune to the channel on which the VOD data is modulated. In the tuner 102 the RF signal is received, the RF component is removed, and a baseband signal is output on the line 190 , In some embodiments, the tuner outputs 102 an IF signal on line 190 which is digitized in the A / D matrix 130 , with the IF downmixed to baseband by the QAM demodulator 146 before demodulation of the constellation points. In some embodiments, conventional carrier recovery and clock recovery are also performed in the tuner 102 and the RF component is removed using a local carrier that is synchronized in frequency and phase with the transmitter of the transmitter to reduce the RF signal to I and Q baseband signals on lines 190 and 191 ,
The RF carrier carrying VOD data is QAM modulated so that the tuner provides a complex, analog baseband signal on line 190 outputs an in-phase and a quadrature component, each having multiple sampling periods, each of which defines the I and Q values of a constellation point. Both components become the A / D matrix 130 sent for sampling with one sample per constellation point on each of the I and Q signals.
The A / D matrix is composed of either two or three A / D converters, depending on whether the DOCSIS modem 70 therein comprises an A / D conversion circuit. Typically, it does that, allowing the output of the DOCSIS data tuner 104 on line 132 is shown as passing the baseband signal straight through the matrix 130 without any sampling by it.
The samples of baseband analog I and Q signals on lines 190 and 191 that include VOD data constellation points are output to the bus 136 , The process of receiving the RF downstream VOD signal and modulating and digitizing each constellation point I and Q value is symbolized by steps 136 , In the preferred embodiment, the clock signal contained in the data (or transmitted on a separate channel in some embodiments) that defines the boundaries of each constellation point is recovered by the tuner 120 and is made available to each of the other circuits that must handle the video data.
The digitized, compressed VOD data is typically QAM-64 modulated. This means that the video and audio data are transmitted in the form of constellation points, each point of which is transmitted during a different time on the quadrature carrier with video, audio and associated constellation points transmitted during different time slots on the same channel , Each video, audio, or associated data point takes the form of a complex number that has a phase and an amplitude value. The QAM demodulator 146 determines the complex value of video, audio and corresponding data points from the compressed VOD data corresponding to each constellation point (step 140 ).
The transport demultiplexer 148 acts to demultiplex the video, audio and associated data points from their respective subchannel time slots (or codes in embodiments where the subchannels CDMA are multiplexed) as symbolized by step 144 , The video demultiplexer receives a control data input from the microprocessor 128 which tells the demultiplexer which subchannel time slots (or codes) to use in retrieving the requested VOD data.
The recovered video, audio and associated data are output in compressed form on buses 150 . 152 and 154 to a conditional access circuit 126 , This optional circuit descrambles the data if the user is authorized to receive the requested program, or makes other known types of conditional access locking if the conditional access function has not already been performed at the headend (step 192 ). If the user is authorized to receive the VOD data, the video, audio and associated data, dots are encapsulated in bus packets that are used on the host bus 156 and sent over the bus to an IP video encapsulation process 158 , Typically, the host bus is a PCI bus, so the known PCI bus interface circuits in the conditional access circuit 126 encapsulate the VOD data in PCI bus packets addressed to the IP video encapsulation circuit (step 192 ).
The IP video circuit monitors the bus 158 packets that are addressed to them, and if they find one, they take the PCI bus packets, which together comprise an IP packet of video data, and re-order the VOD data into an IP packet payload. In cases where the VOD data was never placed in an IP packet format at the headend, the VOD, video and audio data are ordered into IP packets addressed to the network adapter that requested the VOD program , Any associated data is encapsulated in an IP packet addressed to the appropriate peripheral device, such as a PC 22 or the phone 60 in 3 , Usually, the IP destination address to which the video, audio and associated data are bound is contained within the data itself, and when an IP packet has been broken, eg in octets or ATM cells for transmission, the original Obtain IP source and destination addresses as by the methods previously described herein.
In the preferred embodiment, the IP source and destination addresses in the IP packet data within the PCI bus packets are used to assemble an IP packet header after reassembly of the IP packet. The resulting IP packets are transmitted over the line 160 to the routing process 86 (Step 194 ). In embodiments where the VOD video, audio and associated data were never placed in an IP packet format, the host observes 128 where each VOD request comes from on the LAN, and the addresses of the video server to which each is addressed. Then when data arrives from this video server (as determined by the source address the data or network, channel and subchannel on which the data arrives), the host sends data to the IP video circuit 158 where he tells her the IP address of the network adapter to which the video and audio data is to be addressed and the IP address of any other peripheral device to which any associated data is to be sent. The case where the VOD data is not originally encapsulated in an IP packet may occur where a video server is directly coupled to a headend modem or a satellite uplink device or an ADSL CO. The step 194 should be interpreted to also cover this alternative case of constructing IP packets using IP addresses supplied by the host 128 who watched all the outbound VOD requirements.
The routing process 86 receives the VOD-IP packets and reads the destination IP address and determines that the IP address is mapped to the Ethernet address of the network adapter 30 in 3 , The IP packets addressed to this network adapter are then encapsulated in Ethernet packets addressed to the network adapter 30 , and sent to the appropriate network interface circuit in the routing circuit 86 to start on LAN 20 (Step 196 ). The household can have several TV sets, each with its own network adapter. In such a case, the IP destination address will be used in the VOD data to determine which network adapter the program has requested, and the address of this network Ethernet adapter will be used in the Ethernet packet header of the Ethernet packet, in which the VOD data IP packets are encapsulated. The routing circuitry will then determine which LAN and NIC to use to bring the data to the correct TV.
with the VOD data happens when they get to the network adapter,
will be discussed after discussion of ADSL and satellite delivery cases.
DSL Network Delivery
In the case of ADSL delivery (or delivery by any digital subscriber line service with adequate bandwidth), the IP packets may be transmitted from the video server to the ADSL center within approximately 3 miles of the subscriber through a T1 or DS1 line, typically Also, an ADSL downstream connection may be used if the maximum possible load of VOD data sent to that particular CO is low enough (step 198 . 6B ).
From the ADSL center, the video data IP packets are FDMA-multiplexed onto the ADSL downstream carrier and transmitted to the requesting party's gateway via the appropriate subscriber line. At the gateway, the IP packets arrive on the PSTN subscriber line 58 and are coupled via an isolation buffer 204 to the ADSL modem 182 (Step 202 ).
The ADSL modem 182 is a conventional structure and restores the IP packets in a conventional manner and outputs them to the line 188 to the switching process. There, the IP packets carrying VOD data are encapsulated in Ethernet packets addressed to the NIC of the network adapter 30 who requested the video program and are sent to the appropriate NIC in the routing circuit 86 which connects to the LAN to which the network adapter 30 who has requested the VOD program is coupled (step 206 ).
In embodiments where only a single LAN is used at the customer premises, an ADSL modem may be used 200 (shown in dashed lines to indicate that it is an alternative embodiment) with an Ethernet output interface replaced by an ADSL modem 182 with an ADSL modem output, which is directly coupled to the LAN.
Satellite Network Delivery
In the case of satellite delivery of the video data IP packets, the satellite network delivery video server provides the VOD data IP packets to the satellite uplink facility by any suitable means, such as a T1 or DS1 leased line or direct connection to the satellite Uplink transmitter if the video server is located at the uplink facility (step 208 ).
The uplink facility modulates the IP packet data onto the DirecPC uplink carrier or other carrier dedicated to VOD applications and transmits it to a geosynchronous satellite (step 210 ).
A transponder on the satellite then restores the IP packets, and QPSK modulates them (or using another suitable modulation scheme) onto a DirecPC or VOD downlink carrier and transmits them to all the dishes in its earth surface illumination area (FIG. step 212 ).
The tuner 180 ( 4A ) receives the RF signal and performs conventional carrier and clock recovery so that the recovered carriers and clock signals are used can demodulate, detect, and demultiplex the signal as was the case for the tuner's preferred embodiment 102 , The tuner 180 receives data from the host 128 over the host bus 156 , which tells you which downstream channel to tune to, and tunes out all other RF signals. The VOD downlink quadrature carriers are then modulated and I and Q baseband signals are output on lines 216 and 218 (Step 214 ).
Analog-to-digital conversion can be done anywhere behind the tuner 180 and before the IP packetization circuit 158 , However, for parallelism with the HFC case, it will be assumed that A / D conversion in the QPSK demodulator 220 happens before the constellation point demodulation processing. The recovered clock from the tuner 180 is used to circuit the demodulation and A / D conversion processes 220 to synchronize. The I and Q values of the QPSK constellation points are then demodulated to their original analog or digital values to obtain a stream of video, audio and associated data points on the bus 222 (Step 224 ). When demodulated into analog values, these analog values for the I and Q values of each constellation point are later digitized.
The satellite VOD delivery system is very similar to the HFC system in which video programs are delivered on channels, each having a different downlink frequency and each having a plurality of TDMA or CDMA sub-channels. It is the function of the transport demultiplexer 184 , Data from the host 128 which tell him which subchannels to restore and demultiplex the video, audio and associated data points from their respective subchannels (step 226 ). The transport demultiplexer 184 has any conventional TDMA or CDMA demultiplexing structure that can receive data indicating which subchannels to restore and restore them, and may have the same structure as the transport demultiplexer 148 ,
The recovered video, audio and related data are output to a conditional access circuit 186 over buses 228 . 230 and 232 , The conditional access circuit 186 acts to encrypt or pass the VOD data to the subscriber who requested it, only if it is a legitimate subscriber and if this lockout function was not performed on the satellite uplink facility or on the video server (step 234 ). The conditional access circuit may comprise any of the known structures to perform this function.
The conditional access circuit includes a host bus interface circuit (not shown separately) which functions to take the data from the VOD-IP packets (typically the IP packets carrying VOD data are broken for transmission over the channel ) and encapsulate the data in bus packets of the type used on the host bus 156 , eg PC bus packages. These packets are addressed to the IP video circuit 158 (Step 236 ).
The IP video circuit works as described above. In essence, it takes a packet addressed to it from the host bus 156 and either reassembles the IP packet if it was originally an IP packet but was broken up for transmission (such as in ATM cells) or encapsulates the data in IP packets if it never is in an IP packet format were (step 238 ). It is anticipated that the incoming VOD data will include the IP destination address. However, in some embodiments, the host bus will 128 the IP video circuit 158 "When you receive data from the conditional access circuit 186 "They are to be addressed to the IP address of network adapter xx who has requested them." On one or the other way, the IP video circuit sets 158 an IP packet header together for each packet, that of the routing circuit 86 tells you where to send the packet on the LAN. The resulting IP packets become the routing circuit 86 sent over the bus 160 (Step 238 ).
The routing circuit 86 looks at the Ethernet address bound to the IP address, encapsulates each IP packet in an Ethernet packet, and routes it to the appropriate network interface circuit in the router 86 for the LAN to which the network adapter that requested the VOD program is coupled (step 240 ).
Note that if there is any associated data with the VOD program, which is related to the personal computer 22 need to go or to IP phone 60 in 3 , Then put your IP address on the PC or the phone, as the case may be, and the router 86 addresses the Ethernet packets containing this mapped data to the Ethernet address of the PC or the phone or other peripheral device as the case may be, and this is true regardless of whether the VOD data is supplied by ADSL, HFC or satellite (steps 238 and 194 ).
The network adapter structure
and the sub-process for video-on-demand processing
Regardless of which network was used to transmit the VOD program, the data encoding the program is Now encapsulated in Ethernet packets and placed on the LAN. A block diagram of a typical network adapter 30 in 3 is shown in 5 , The function of the network adapter is to pick up the appropriate Ethernet packets from the LAN, extract the video and audio data, and convert it to an NTSC or PAL or SECAM signal, or to a video signal that can be fed into a video input a TV.
Each network adapter has a network interface card 84 which couples the network adapter to the physical medium of the LAN. Network interface circuits for Ethernet are well known and will not be further described herein. Every NIC on the LANs 18 and 20 has a unique Ethernet address, which maps to one or more IP addresses. Therefore, if an IP packet is sent to the IP address of the network adapter 30 When the gateway arrives, the routing table of the gateway will map this IP address to the Ethernet address of the network adapter. The entire IP packet, header and everything, will then be encapsulated in an Ethernet packet with the destination address of the Ethernet packet, which is that of the network adapter.
All Ethernet packets are received by NIC 84 but only packages connected to the network adapter 30 are kept are kept. If an ethernet packet connected to the network adapter 30 is addressed, it is examined to see if the Ethernet address matches the address of the network adapter, and if so, the packet is routed through the Ethernet protocol stack, where the Ethernet head is removed and error detection and correction is performed on the package. The resulting IP packet is then routed to the IP video circuit 242 (Step 244 ). For outbound packets, such as menu requests and VOD request packets, the Ethernet protocol stack is leading to NIC 84 the CSMA / CD transmission and collision detection protocol and transmits the packet to the LAN.
The IP packets from the NIC 84 are examined by the IP video circuit 242 to determine if they are addressed to the network adapter and if they are graphics data or video data. The IP packet header is removed and payloads of packets containing video / audio data are transmitted as a bit stream to the MPEG decoder 246 , and packets containing graphics data are transmitted as a bit stream to the 2/3 D graphics circuit 83 (Step 248 ). In some embodiments, the menus will not be sent as separate data, but simply be video frames that are digitized and compressed. In such embodiments, the bus is 87 unnecessary.
The MPEG decoder 246 decompresses the compressed video and audio data bits and generates an uncompressed audio bitstream on the line 250 and an uncompressed video bitstream on the line 252 (Step 258 ).
The audio bitstream is enhanced for stereo and filtered and then converted to an analog signal in any conventional audio processor 254 (Step 258 ). In alternative embodiments, the uncompressed audio data is not processed to expand or convert to stereo or filter them, and they are simply converted to an audio signal.
The data output on the line 252 is a digitized YUV format video signal. The video processor 256 filters the video signal to expand it (step 258 ). The combination of the video processor 256 and 2/3-D graphics 83 are commercially available in integrated circuit form from ATI or C. 3
The digitized YUV format video signal on the lead 264 (or 252 when the video processor 256 not used) is converted by the video encoder 260 into an NTSC, PAL, SECAM or composite format video signal that can be displayed on a TV (step 262 ). If the output format is composite video, the composite video signal is input to the TV video input via the line 266 (Step 262 ). Similarly, the audio processor converts the digitized, uncompressed audio data into an audio signal on the line 270 for pairing with the audio input of a TV (step 272 ). When the output signal from the video encoder 260 is an NTSC, PAL or SECAM format, the signal is modulated onto an RF carrier at a locally unused frequency, such as channel 3 , by a video modulator 276 (Step 274 ).
Broadband Internet access
are very slow over
Modems. It is much more useful
surfing the internet with a much wider bandwidth, at least
Referring to the 7A - 7? There is shown a flowchart of the process of high bandwidth surfing the Internet using one of the HFC, satellite DirectPC or DSL networks. In step 278 starts the personal computer 22 in 3 or network computer (sometimes referred to hereinafter as NC) 24 or 26 his browser and enter an URL of a web page to look at. The network computers 24 and 26 do not have any local hard drives, so they run their browsers from the hard disk of the personal computer via known techniques of executing shared software on a server over the network or over a WAN such as the Internet. Typically, the network computers indicate which program they want to run by double-clicking an icon on their desktops. This action is converted into a request to download the program from a server on the LAN or WAN to the RAM of the network computer. This request is converted by the NIC of the network computer into an Ethernet packet directed to the server on the LAN. The NIC of the server reads the packet, opens the file and generates one or more Ethernet packets directed to the network computer receiving the packets, and loads the browser program or other application that requires internet access into the RAM and starts its embodiment.
When the program to be executed resides on a server on the Internet, the step of double-clicking the icon of the program to be started is converted by TCP / IP protocol software layers in the network computer (typically stored in non-volatile memory EEPROM or ROM ) into an IP packet addressed to the server storing the application program to be executed. The IP packet is then encapsulated in an Ethernet packet by the NIC of the NC, which is connected to the gateway 14 is addressed. At the gateway, the Ethernet packet is received by the NIC, and the Ethernet header is removed by the routing process 86 , The packet is then routed to the appropriate upstream medium transmitter for which the user subscribes or whichever is the cheapest for Internet access if the user has installed DSL, satellite and HFC modules - or any combination thereof (least cost routing) -Process). In other words, the IP packet will be routed to the DOCSIS modem 70 for upstream transmission via the HFC 10 or the ADSL modem 182 if the DSL service is to be used or to the conventional modem 280 (which may also be a conventional FAX / data modem) if satellite download service is to be used over DirectPC. The IP packet is sent by one of these media to the headend, ADSL CO or dial-up to the satellite uplink facility. At the destination, the IP packet is recovered and routed through a router at the destination to the Internet server, which stores the application to be executed.
The Internet server then sends the program to be executed to the network computer by encapsulating the data of the program in IP packets addressed to the NC that requested them. These IP packets arrive at the gateway and are recovered by the DOCSIS modem, ADSL modem or satellite receiving circuit to be described below, and are sent to the routing process 86 , There they are encapsulated in Ethernet packets addressed to the NIC of the NC that has requested the program and launched on the LAN. The NC receives the packets, separates the data from the program, stores them in its RAM and starts executing them.
The user then enters the URL of the web page he wants to visit (step 278 ). The browser or other application then routes this URL down to the TCP / IP protocol software processings that are running on the computer that translate the URL into an IP packet requesting that the web page be submitted to the computer URL is downloaded to the computer that asked for it, as described by the source address of the IP packet (step 282 ). This IP packet is then encapsulated in an Ethernet packet addressed to the gateway 14 through the NIC of the NC or PC (step 284 ).
The NIC of the gateway (not shown separately in 4A ) receives the Ethernet packet, removes the Ethernet header after error detection and correction, and routes the IP packet up to the routing process layers. The router looks up the destination address in its routing tables and forwards the packet to one of the upstream transmitters (step 286 ). If the user has only installed a network interface, such as only one HFC interface or only one ADSL interface (as determined either by an investigation process being performed by the router or by configuration data), the IP packet is forwarded to the upstream transmitter , However, if the user has installed more than one network interface, the router may forward the IP packet to an upstream transmitter based on some criteria, such as user dialing as indicated by a management and control packet sent to the gateway Field in the IP packet, through a random or competitive selection process, or through a low-cost routing algorithm that automatically selects the cheapest service for broadband Internet access. The step 286 is intended to represent any of these methods of selecting the upstream transmitter.
If the upstream transmitter is the DOCSIS modem 70 is, the IP packet is transmitted upstream via a virtual channel dedicated to this gateway or assigned during transmission by the headend. The virtual channel can be established by TDMA, SCDMA or CDMA or possibly by FD MA. The CO modem restores the IP packet and forwards it to a router coupled to the headend (step 288 ).
If the upstream transmitter is the ADSL modem 182 is, the IP packet is modulated on the upstream carrier and transmitted over the PSTN subscriber line 58 to the ADSL modem at the CO. There it is restored and routed to a router that is connected to the Internet (step 288 ).
If the downstream medium will be the satellite downlink, the upstream transmitter is the conventional modem 280 , This modem dials a modem at the satellite uplink facility and transmits the IP packet there. The IP packet is recovered and forwarded to a router coupled to the Internet (step 288 ).
The router sends the IP packet to the web server at the URL (step 290 ), which opens the web page identified in the URL, and begins to send the web page data back to the router as a series of IP packets (step 292 ).
The IP packets arrive at the router and are sent to the appropriate downstream transmitter. The step 294 is intended to represent downstream transmission over any of the HFC, DSL or satellite media. In the case of HFC delivery, the downstream transmitter will be the headend modem. The headend modem will either transmit the IP packet on the downstream carrier to all gateways or transmit it on a downstream virtual channel associated with the gateway at the premises of the PC or NC that requested the website (step 294 ).
If the downstream medium is the satellite downlink, the router sends the IP packets to the uplink transmitter, which transmits them to the satellite. A transponder on the satellite receives the packets and transmits them back on the downlink channel (step 294 ).
If the downstream medium is a DSL subscriber line, the router at CO sends the IP packets to the ADSL modem at the CO, which modulates them onto the downstream carrier (step 294 ).
The step 296 represents the recovery of the IP packets at the gateway, regardless of the downstream medium, transmission to the router, protocol conversion and routing and transmission out on the appropriate LAN. The details of how to do this in the gateway for each different downstream medium follow.
In the case of HFC downstream delivery, the tuner filters 104 everything except the DOCSIS downstream beam and removes the RF component. The resulting baseband signal is passed through the A / D matrix on the line 132 to the DOCSIS modem 70 , There, the IP packets are restored and sent to the routing circuit 86 over the bus 300 , Although shown as a separate bus, in some embodiments it may actually be the host bus 156 be with the ip packets sent to the host microprocessor 128 by encapsulating in PCI bus packets addressed to the host. Similar for all other buses that are shown in 4A that are in the routing circuit 86 go in or come out. The router 86 looks up the destination address in the IP packets and determines that they are to PC 22 or one from NC 24 or 26 are addressed. The router then encapsulates the IP packets into Ethernet packets addressed to the appropriate PC or NC and directs them to the NIC for the appropriate LAN that is connected to the PC or NC that requested the data ( step 296 ).
In the case of satellite downstream delivery, the tuner becomes 302 in 4B instructed by the host 128 to tune to the DirectPC downstream QPSK modulated carrier. The tuner rejects all other signals and restores the carrier and synchronizes a local oscillator to produce two coherent reference signals which are phase and frequency matched to the two quadrature carriers used to transmit the downstream IP packets. These local reference signals feed two correlators in the tuner, one for the in-phase channel and one for the quadrature channel. Each correlator consists of a multiplier and an integrator. Digital QPSK transmission and transmitters and receivers therefor as well as other modulation and demodulation schemes and carrier and clock recovery circuits are described in Haykin, Communication Systems, 3rd Edition (Wiley & Sons 1994) ISBN 0-471-57178-8, which is incorporated herein by reference is incorporated. The digital satellite receiver channel is not limited to QPSK modulation, and any modulation and / or multiplex scheme used for downstream transmission now or in the future may be used with appropriate adaptations to the gateway satellite digital data receiver.
The output from the receiver 302 connects via I and Q buses 306 and 310 to a QPSK demodulator 304 which functions to recover the IP packet data and encapsulate it in bus packets for the host bus which are addressed to the routing circuit 86 , The QPSK demo dulator 304 typically includes a decision device that receives the baseband I and Q channel data and compares it to the decision threshold of zero volts. If the I-channel voltage is greater than zero, a logical 1 decision is made, but if the voltage is less than zero, a logical 0 decision is made. If the Q-channel voltage is greater than zero, a logic decision of 1 is made, but if its voltage is less than zero, a decision of logic 0 is made. Finally, the two binary bit sequences which define the IP packets coming out of the decision circuit are again combined in a multiplexer in the demodulator 304 and sent to bus interface circuit in the demodulator 304 for encapsulation in bus packages and transmission over the bus 312 and the host bus 156 to the router 86 , The router receives them, removes the host bus packet headers, looks up the IP destination address, and finds out that they are addressed to the PC 22 or one of the NCs. The IP packets are then encapsulated in Ethernet packets (or whatever other packet format is used on the LANs 18 or 20 ) addressed to the PC or NC that requested the data and sent to the appropriate NIC (step 296 ).
If the downstream medium is an ADSL subscriber line, provides a conventional ADSL modem 182 in 4A Restore the IP packets and send them on the bus 188 to the router 86 , The router receives them, removes the host bus packet headers (if the bus 188 actually the host bus 156 is), look up the IP destination address and find out that they are addressed to the PC 22 or one of the NCs. The IP packets are then encapsulated in Ethernet packets (or whatever other packet format is used on the LANs 18 or 20 ) that are addressed to the PC or NC that requested the data, and they are sent to the appropriate NIC (step 296 ).
The NIC of the PC or NC that requested the data receives the Ethernet packets, performs error correction, and removes the Ethernet heads. The resulting IP packets are routed out to the TCP / IP protocol layers, where the IP packet headers are removed, and the TCP protocol ensures that all packets have been received. The payload data is then sent to the application that requested it for display (steps 308 ). Processing by the PC or NC of the IP packet data and Ethernet packets is the same as with PCs on a LAN sharing modems and dial-up connections to the Internet via ISPs, and this technology is incorporated by reference.
Distribution of analogue video transmission via satellite
or terrestrial antenna
One of the advantages of the gateway 14 it is also that it can be used to house analog TV broadcasts to TVs using the LAN, eliminating the need for separate wiring.
The tuner 314 Starts this process by receiving control data from the microprocessor 128 which define which C-band analog video channel has been requested by the user. The tuner 314 may be any conventional C-band satellite tuner that is modified to receive digital control data from the host 128 is accepted to control which satellite and which transponder to tune as opposed to receiving this information directly from the remote control or from the front panel switches. In the home network described herein, users request C-band transmission channels via their IR keyboards 34 or remote controls 80 in 3 , These requirements are encapsulated in management and control Ethernet packets addressed to the host CPU 128 through the network adapter 30 , The host CPU receives them and generates a PCI bus packet on the bus 156 that is addressed to the tuner 314 telling him which channel to tune to, ie which satellite to pan to and tune to which transponder or channel in the downlink transmission.
The RF (or IF) output of the tuner 314 on the bus 134 is then digitized by the analog-to-digital converter 316 , The digital samples on the line 318 are input to a video demodulator 320 which functions in the digital domain to demodulate the digitized analog video signal by removing the RF component. The video demodulator 320 puts digital data on the line 322 which represent a conventional baseband NTSC, PAL or SECAM format video signal.
The digital data on the line 322 are at too high a bitrate to send over the LAN because uncompressed video transmission consumes more than 212 Mbps of bandwidth. Therefore, the video data must be compressed. MPEG-II compression is preferred, but any other form of compression currently known or to be developed in the future will be suitable since the form of compression is not critical. MPEG-II compression circuitry is well known and is used for the MPEG coder 326 , However, MPEG compression does not compress NTSC, PAL, or SECAM format signals. They must first be converted to YUV format luminescence and chrominance signals. This wall This is done in the video encoder 324 , which is a known type of circuit in any video system that uses MPEG-II compression.
The compressed video data is encapsulated in PCI (or other type) bus packets addressed to the IP video circuit 158 in 4A , There, the compressed video data is encapsulated in IP packets addressed to the network adapter of the TV where the request comes from and the satellite C-band video channel is to be viewed. The IP video circuit 158 determines which IP destination address to use when constructing the IP packets over received data from the host microprocessor 128 , When the original request has been received, the host microprocessor determines 128 also in addition to being the tuner 314 tells to which channel to tune, from the source address of the Ethernet packet carrying the request, the network adapter that requested the data from TVs. The IP address of this network adapter is encapsulated in a PCI bus packet and transmitted over the host bus 156 to the IP video circuit. The IP packets encapsulating the digitized C-band video channel are then transmitted over the bus 160 to the routing circuit 86 , The bus 160 just the host bus 156 in embodiments, where the routing process is performed by software on the host 128 ,
The routing process 86 is a conventional IP to Ethernet routing process that examines the IP packet destination addresses and looks up the corresponding Ethernet addresses. The IP packets are then encapsulated in Ethernet packets and routed to the appropriate LAN network interface card for LAN 18 or 20 depending on the Ethernet destination address of each packet. Conversely, the process works for incoming Ethernet packets from the LAN (s).
When the IP packets reach the network adapter of the TV that has requested the CATV channel, they are converted into a video signal that can be displayed by the TV through the above in connection with the discussion of 5 described circuit.
Terrestrial broadcast reception
Reception and distribution of standard TV broadcasts, which are received via an antenna, which is coupled to the gateway 14 , are very similar. A standard TV antenna 328 is coupled to the gateway through a coax or double feed cable 330 , A TV tuner 332 Tunes the requested channel and outputs the desired channel as an RF or IF signal. The tuner 332 may be a conventional TV tuner modified to receive digital control data from the host computer 128 which control which analog TV transmission channel the tuner selects.
The A / D converter 334 samples the output RF or IF and feeds the samples to a video demodulator 336 , There, the signal is demodulated in the digital domain to remove the RF component. As is the case for all the analog signal receiver circuits for both HFC and satellite, the analog-to-digital conversion can be made anywhere along the line of circuits, including just ahead of the MPEG encoder.
The exit 338 is a digital version of an NTSC or PAL or SECAM signal. It is fed into a video decoder 340 that transforms it into a YUV format. The YUV signal is then compressed by the MPEG encoder 342 and in bus packets of the format used on the host bus 156 (typically PCI) and addressed to the IP video circuit 158 ,
The IP video circuit removes bus packet headers (and can perform error detection and correction) and encapsulates the compressed video data from the PCI bus packets into IP packets addressed to the network adapter of the TV where the requested channel is to be viewed. The IP packets are then sent to the router 86 where the destination address is looked up and the IP packets are encapsulated in Ethernet packets that are addressed to the same network adapter and started on the appropriate LAN.
is synchronous or stream-oriented. On the other hand, it is more traditional
LAN traffic burst-like. LANs
have not been developed to support power traffic, and
therefore it is possible
that a 10 Mbps 10BaseT Ethernet LAN is temporarily insufficient
Has bandwidth to support the load, especially if there
There are several TVs, each with a different channel
request, together with other simultaneous traffic, whereby the 10
Mbps bandwidth is shared. Video is high-bandwidth intensive,
even 100 Mbps LANs have problems in supporting
High Quality Video
mixed with more traditional LAN traffic.
Accordingly, it is within the scope of the genus of the invention to have higher capacitive LANs for LANs 18 and 20 to use. Specifically, these LANs may be Fast Ethernet, Switched Ethernet, FDDI, ATM and Fiber Channel Arbitrated Loop. Such LANs are described in Tannenbaum and Horak, supra, and Kembel, Arbitrated Loop, Connectivity Solutions, a division of Northwest Learning Associates, Inc. of Tucson, Az, (1997) ISBN 0-931836-82-4.
Distribution of DirecTV digital video transmission
The gateway will include a bus bay for a module that can receive regular scheduled DirecTV and other format digital video transmissions on downlinks from a satellite. A tuner 344 Serves to receive digital control information from the host microprocessor as to which channel on the downlink a user requested. The tuner then tunes to this channel and rejects all other signals, and a QAM demodulator demodulates the signal to recover the transmitted data and gives a complex baseband signal to the line 348 out. Conventional QAM-modulated digital data receivers are taught in LEE & Messerschmitt, Digital Communications, 2nd Edition, (Kluwer Academic Publishers 1994) ISBN 0-7923-9391-0, Section 6.4.3, pages 203-208 and 6 - 18 and 6 - 19 The whole of this book is thereby incorporated by reference. Typically, the tuner 344 comprise a bandpass filter to tune the desired channel and reject out-of-band signals, and doubling as an anti-aliasing filter. Typically, the signal is then digitized, and a phase splitter (a filter that passes only frequency components in the positive half of the Fourier spectrum and rejects Fourier components in the negative half) operates in the discrete time domain to detect the negative half of the Fourier component. To remove frequency components of the received spectrum, to output an analytic signal. Then, the positive half of the frequency components of the received signals is demodulated, ie, the RF carrier component is removed by mixing with a local carrier synchronized with the transmitted carrier.
6 - 16 by Lee et al. on page 204 illustrates three different configurations of a QAM tuner.
It is the function of the QAM demodulator 346 to send the current icons. This is usually done by scanning and separating. A complete QAM tuner to bring the received signal back to baseband and demodulator to recover the transmitted symbols is shown in FIG 6 - 18 (b) by Lee & Messerschmitt for the real-valued case and is composed of two mixers that move the received spectrum back to the baseband by multiplying it by quadrature local carriers and two receive bandpass filters to reject out-of-band signals and only the positive half of the Fourier components of In. Forward phase and quadrature signals. The I and Q signals are then sampled at the symbol rate and passed through a splitter to recover the symbols actually transmitted. A more complete representation of a purposeful QAM receiver including both predecessor equalization and successor equalization and carrier and timing recovery is shown in FIG 6 - 23 from Lee & Messerschmitt. Preferably, there will also be an error detection and correction circuit (not shown).
After the symbols of the compressed video program are restored, a conventional transport demultiplexer receives 350 digital control input from the host with respect to which subchannel to find the video program that has been requested and demultiplexes the audio, video and any associated data from these subchannels. To help manage the load on the LAN, the transcoder becomes 352 used to down-convert the bit rate of the compressed video to a lower rate, if necessary, due to current load conditions on the LAN. Transcoders are known and commonly available from Imedia of San Francisco, California, and now by the assignee of the present invention.
The output data of the transcoder is supplied to a conventional conditional access circuit 354 which decrypts the data if the subscriber is authorized to receive the program. Alternatively, the conditional access circuit 354 act to decrypt the original encrypted data if the user is an authorized subscriber, and then re-encrypt the data prior to transmission on the LAN using the new C5 encryption standard. The re-encrypted data is then packetized into bus packets and transmitted over the host bus 156 to the IP video circuit 158 , There they are encapsulated in IP video packets that are addressed to the network adapter that requested the program, and they are sent over the data path 160 to the Roting Circuit / Process 86 , The routing process looks up the destination address and maps it to the LAN address of the network adapter and encapsulates the data in Ethernet packets and sends them to the correct NIC for transmission over the LAN. At the network adapter, the packets are processed as previously described in connection with the description of 5 to convert the data into NTSC, PAL or SECAM video signals and the corresponding synchronized audio. When CS encryption is used, the data remains encrypted in all stages until it is converted in analog video and audio signals.
A conventional DirecTV receiver that is modified to receive digital control data telling it which channel and subchannel to tune may alternatively be used for the tuner 344 , the QAM demodulator 346 and the transport demultiplexer 350 , Alternatively, the satellite receiver taught in US Patent 5,983,071 may be used, but modified to remove the audio decoder 160 , the D / A converter 164 , the video decoder 170 and the NTSC coder 174 , These functions all happen with the network adapter after distribution over the LAN. If the receiver of US Patent 5,983,071 is substituted for the tuner 344 , the QAM demodulator 346 and the transport demultiplexer 358 and the conditional access circuit 354 , the audio and video output currents are on lines 162 and 172 supplied by the patent to the transcoder 352 , The receiver taught in U.S. Patent 5,983,071 may also be used instead of the tuner 102 , the A / D matrix 130 , the QAM demodulator 146 , the conditional access circuit 126 and the transport demultiplexer 148 , This receiver will in turn be modified to remove the following components taught in the patent: audio decoder 160 , the D / A converter 164 , the video decoder 170 and the NTSC coder 174 , These functions all take place in the network adapter after distribution over the LAN. The conditional access circuits 126 and 186 Both may be modified as described above to re-encrypt the recovered data under the C5 standard to prevent digital copies from being made. If the receiver of US Patent 5,983,071 is substituted for the tuner 102 , the QAM demodulator 130 and the transport demultiplexer 148 and the conditional access circuit 126 , the audio and video output currents are applied to the lines 162 and 172 of the patent, either to a transcoder, if present, or to bus interface circuitry (not shown), which packages it and sends it to the IP video circuit 158 over the host bus.
Pay-TV-drawing technology gateway compatibility
The gateway 14 can also be used to receive pay-TV or free regular scheduled transfers from digital or analog video programs. Drag technology means a video server at or coupled to the HFC headend, ADSL-CO or satellite uplink, which has a regular schedule of video programs that it outputs on specific channels at specific times. A menu displayed on the television in the manner described or published elsewhere herein is used by the user to select the program the user desires to see. The user selects the program he wishes to see at the time the program presumably starts by inputting the program number (the program number can be mapped to the service provider and the video server IP address, or this information can be manually be entered) on its remote control 80 or keyboard 34 , This program number is encapsulated in an Ethernet request packet and transmitted to the gateway where it is routed to the host. The host 128 then sends the appropriate command data to the tuner via the host bus 102 or 100 or 180 or 313 or 344 or 332 or ADSL modem 182 to tune to the appropriate channel, depending on which medium the program will arrive on. In the case of digital video, the host also sends control packets to the transport demultiplexer 350 or 184 or 148 to control them, to demultiplex the compressed video and audio signals from the correct subchannels. When transcoders are used in the digital or analog video receiver modules, the host will monitor the load status of the LAN in any known manner, and appropriate control packets will be sent to the transcoders via the host bus to control the bit rate of the compressed video over the LAN so as not to exceed the available bandwidth under varying load conditions.
Since there is a LAN running through the customer premises, it is useful to use the LAN to provide video and audio and FAX telephony data to the video phones, telephones, FAX devices and FAX modems in the premises to distribute. Since all of these physical telephony devices are also coupled to a computer, it is useful to have an IP and / or PBX telephony module 353 to include in the gateway to provide functionality that the user was previously unable to obtain from the POTS service. POTS service can provide conference call, call forwarding, caller ID, voice mail and pager notification of voice mail messages as well as other services via facilities such as Centrex provided by the CO switch. However, all these services cost extra money and can be implemented locally in the gateway by using "PBX on a card" expansion circuitry to extend the functionality of the host 353 To extend the functionality of DOS and Windows-based personal computers to include PBX functionality, voice mail, and a host with other features is commercially available as the VS1 and Incli ne systems from Picazo Communications, Inc. of San Jose, California; and Netphone, Inc. of Marlborough, Massachusetts, and Altigen Communications, Inc., the details of which are incorporated herein by reference. The Netphone PBX is based on a card technology which can be used to connect the circuit 353 is described in U.S. Patent 5,875,234, which is incorporated herein by reference. This patent essentially teaches a PBX circuit on an expansion card coupled to the host bus of a network server. The PBX cards can establish and maintain phone calls and perform normal PBX call control functions. The PBX card can be controlled by telephony-embedded applications on the server / gateway or by telephony-embedded applications running on PCs over the LAN connection to the gateway. Any known expansion circuit to add PBX functionality to a LAN server can be used for the circuit 353 regardless of whether it is implemented in a single board or more than one.
Typically, the circuit will 353 have their own switching circuit for connecting telephone calls from extension telephones, which are coupled to conventional telephone lines, to CO trunk lines 58 and vice versa.
In some embodiments, the PBX functionality alone may be sufficient. However, the use of the Internet for telephony is a growing market, and web pages such as www.net2phone.com already exist to allow remote telephone conversations to take place over the Internet, regardless of distance for 10 cents per minute. To allow users to take advantage of these services, PCs are on LANs 18 and 20 must be equipped with microphones and speakers. In such a class of embodiments, the IP & PBX telephony circuit becomes 353 Circuits include digitizing analog speech signals arriving from extension telephones over conventional telephone lines 354 , The IP & PBX telephony circuit 353 may also include packetization circuits in some embodiments to receive Ethernet packets carrying digitized voice from the PCs to LANs 18 or 20 from routers 86 over the bus 356 and these packet into IP packets that are addressed to the Internet server that provides the IP telephony services. These IP packets are then sent back over the bus 356 to the router 86 where they are routed to the server identified in the destination address of the IP packet. Routing may be least cost routing if multiple high-bandwidth upstream media, such as HFC and ADSL upstream high-speed Internet access modules such as DOCSIS modem 70 and ADSL modem 182 in which the gateway is present. In other embodiments, the PBX expansion module becomes 353 Make call control circuit and provide other services between extension lines 354 and the CO trunks, and analog telephone signals from the extension phones on line 354 will be digitized and packetized into an IP packet addressed to an IP telephony server on the Internet, whose IP address is fixed and known to be the IP address, to the telephone data from the conventional POTS telephones to be addressed.
Then, instead of transmitting the data of Ethernet packets carrying telephony data from PCs, telephones and FAX devices on the LAN for encapsulation into IP packets through the IP and PBX telephony module 353 IP packet encapsulation is made at the source. In other words, if the PC 22 or NC 24 or the phone 60 or the FAX 64 When customer premises want to send data to an IP telephony server on the Internet, the digital data generated by the source device will be encapsulated by the source device into IP packets addressed to the IP telephony server on the Internet. These packets will then be encapsulated in Ethernet packets and sent to the gateway 14 , The gateway 14 will then remove the Ethernet packet headers and route the trapped IP packets to the server on the Internet to which they are addressed via the DOCSIS modem 70 , the ADSL modem 182 or possibly through the conventional modem 280 in 4A (although using the conventional modem only makes sense if media with higher upstream bandwidth are not available).
of the gateway
Referring to 8th There is shown a block diagram showing the software architecture and modular design of the gateway / LAN server 14 illustrated. As mentioned above, in alternative embodiments, the gateway 14 in fact, there are two or more servers to split the work, but each is coupled to the expansion modules through a bus / LAN structure 156 , For example, one server may only run the PBX control software and IP telephony software, and another server will only perform the management and control and routing processes needed for the push and pull video applications and high speed Internet access, and may use any routing Perform functions needed for IP telephony with the first server.
The software processes in the host or server are in connection with the operation system 358 and use its application programming interface (API) to transfer messages between processing and to data to the LAN interface or NIC 360 and the host bus 156 to send. The data paths between the different software processes and between the different processing and NICs 362 and 364 and the host bus 156 about the operating system are symbolized by the data path 366 , This data path represents any of the typical methods and apparatus for transferring data between processes or between processes and circuits in the gateway. For example, NIC # 1 362 may receive an Ethernet packet bearing a request for a video-on-demand program addressed to the management and control process. One-sided can NIC 362 transfer this packet to the routing process 86 by writing the data into a board-own scratch pad RAM and invoking a software interrupt for the routing process 86 and sending a pointer to the message in RAM. The routing process then executes an interrupt service routine for this interrupt and reads the data from the scratch pad RAM at the address supplied to it with the interrupt or at a pre-assigned address stored in an interrupt table. Processes and circuits may also forward messages by writing them to predetermined locations in shared address spaces in the RAM 129 with the target circuit or process and then putting an interrupt bit and storing an interrupt number in a register. The interrupt bit causes the host to execute a generic interrupt service routine to retrieve the interrupt number and then look up the interrupt number in an interrupt vector table. The table would indicate the address of the start of an interrupt service routine for the number. Each circuit or process would have an interrupt number and an associated interrupt service routine. The service routine pointed to by the vector table would then be executed and retrieve the data and return it to the process or circuitry associated with the interrupt. Each of the expansion modules would forward data or IP packets to the routing process 86 or the IP video process 158 in this way.
A management and control process 368 Restores video on demand and other requirements for services and data as described in the detailed description of each module. These other requirements may include the numbers of CATV or terrestrial channels to tune to, or requirements for DirecPC or ADSL or HFC high-speed Internet access. Other data that the management and control process will recover in alternative embodiments is LAN-available bandwidth status and other network management type data. In response, the management and control process sends appropriate control data to the tuner, transport demultiplexer, transcoder, conventional access circuits, IP video process and other circuitry or processes to manage the recovery of the requested data and distribute it to the appropriate peripheral device or data upstream on certain upstream channels. These upstream channels may be preempted or assigned by downstream control messages from the headend or the ADSL CO or satellite uplink server.
The routing process 86 translates between IP and Ethernet or other LAN protocols and works as described above. The IP video process 158 encapsulates data sent to it via the host bus into IP packets addressed to the appropriate peripheral device.
The IP telephony and other embedded telephony and PBX processing by the block 370 For example, there may be 5 conventional or LAN telephones in the home, each of which is primarily answered by a person in the home the family. One of the processes of Block 370 can implement direct-inward dialing so that each phone has its own virtual phone number that an outsider can dial, for example, to talk to teenager Judy, without the inconvenience of accidentally talking to her dad. Similarly, two extension phones may wish to make a conference call with a telephone in another state. The PBX control software controls the switch in the PBX module 372 to implement any of these desired PBX features. The IP telephony process performs IP telephony by, for example, receiving digital data from conventional POTS telephone via the telephony module 372 and encapsulating it in IP packets through the router 86 be directed and vice versa. The IP packets coming from LAN-active phones 60 and 62 are simply routed directly to the router 86 ,
Similarly, a database program or word processing program running on a computer or NC on the LAN can be made phone active. For example, a Rolodex file created by a word processor may include telephone numbers, and the user may look up a person by name and then double-click the telephone number mer. This double-click will be changed by the telephony-embedded application into an Ethernet packet requesting that the telephone number be dialed. This Ethernet packet is sent to NIC 362 or 364 and then forwarded up to the router 86 , The router removes the Ethernet header and forwards the data of the request to a PBX application represented by the block 370 , The PBX application makes a function call to a library program of the OS 358 via the standard TAPI interface 374 ,
TAPI interface represented
a collection of predefined Windows function calls, each one of them
Library program from a telephony-dynamically linked library of programs
calls. The TAPI function calls
provide a standard telephony programmatic interface
to perform the phone functions
want. The basic level of functions allows application programs,
perform base-incoming and outgoing voice and data calls
Provide programs that can be called by
Initialize and open
TAPI lines, reading and writing different parameters,
the one line device
control the details of placing outgoing voice or
Handle data calls or responses to incoming voice or data calls,
and / or forming telephone "addresses" or call sequences, manipulating
Call handling etc. Put other programs in the TAPI library
more advanced features, such as digit or tone generation
and recognition, call acceptance and rejection, rerouting, call forwarding,
Parking, holding, conference, etc., when the latter advanced
Features become complementary
Called telephony services and allow several telephone handsets or
other line devices,
only a single CO pipeline
to divide or divide multiple CO pipelines in a PBX-type arrangement. The transmission lines
be analogous, T1, IDSN or DSL. Because TAPI is also the logical construct
from telephone devices
the NCs and PCs out there
the network with TAPI libraries actually more line-virtual
Phones have implemented in accordance with executing
Code, so every room with a PC in it is also a multi-line phone
can, that is capable
Conference, holding, parking, telephone forwarding and other advanced
those for standard home phones
are not normal.
TAPI services focus on "line devices" as a means of transporting information from one place to another A line device may be a standard telephone handset, a fax card, a data modem, a telephony card, or any physical device coupled to a telephone line. In the system that is in 8th shown are the ADSL modem module 378 , the conventional modem module 380 and IP and PBX telephony module 372 all line devices. Since a line device is a logical construct, TAPI can see multiple line devices, all coupled to the same physical telephone line. A TAPI call control program (dialer.exe) may receive multiple concurrent TAPI service requests from, for example, the PBX application, the IP telephony application and other telephony embedded applications, all represented by the block 370 , and arrange them all in line for operation.
between the application programs and the TAPI library are handled by the Windows message function
using predefined TAPI data structures. telephony libraries
Operating systems can
to be used alternatively for the
Windows TAPI library
and the data structures and message functions of the operating system
be replaced, which is in use.
TAPI is structured and how application programs are written
to exploit these resources, everything is defined in Amundsen,
MAPI, SAPI & TAPI
Developer's Guide, (SAMS
Publishing 1996) ISBN 0-672-30928-9, which is hereby by reference
Returning to the current example, the TAPI program executes a function call and turns it into the telephone service provider process 376 and forwards him the number to dial. The TSP layer 376 The TAPI library program isolates the need to know the details of the specific hardware installed, and isolates the particular hardware that is installed from it for the specific telephony-embedded application programs that are present. She is a translator between the TAPI world and the hardware world. In other words, the TSP layer implements 376 the TSPI functions used by TAPI implementation. Each TSP then uses interface, whichever is appropriate to control the telephony hardware to which it is connected. The TSP layer 376 and the PBX card driver layer 378 may in fact be combined in some embodiments, and in other embodiments, the TSP layer may be used to interface with other telephony hardware, such as a FAX modem extension module 380 at the gateway through which FAXes can be sent using data received from PCs that do not have FAX modems or connections to have phone lines available in their place on the network.
Assuming that TSP and PBX card drivers are separate processes, either TSP calls 376 or TAPI program 374 then the appropriate function call from a PBX card driver process 378 and forwards him the number to dial. The PBX card driver speaks the specific language of the IP and PBX telephony module 372 and sends it an appropriately formatted message to control the switch and other circuits thereof to occupy a CO trunk and generate the appropriate DTMF tones to dial the requested number when a ringing tone is detected.
When the person answers, the voice is digitized by a codec in the PBX card 372 and the data is passed back to the PBX card driver, which then routes it back through all the layers to the router. The router encapsulates the data in an Ethernet packet addressed to the telephone or other trunk device that made the call and routes the packets to the appropriate NIC. The NIC transmits the packets over LAN to the network adapter of the phone or PC or NC from which the call originated. The reverse is for speech originating from the PC, NC, or telephone that gives the call to the person who answered the phone.
Host bus is paired via
Bus connectors or expansion slots to one or more
Expansion modules containing the transmitter and receiver circuits and others
Implement interface circuits necessary to
to connect the gateway
to the satellites, HFC, POTS or DSL media or any other media,
such as. Power lines or wireless subscriber lines,
which may be developed in the future. Modules are only shown
for currently existing ones
Technologies, but it is certain that new upstream and downstream media
will follow, and the genus of the invention includes expansion modules
one of the type needed to adapt to these newer ones
To connect media.
The ADSL modem module 378 can any conventional ADSL modem 182 or SDSL modem or any other modem for connection to any type of digital subscriber line that can be digitally controlled by the host 128 , There will be any connector and isolation circuits 204 which are needed to connect to the DSL CO trunk.
The FAX / data modem module 380 may be any conventional FAX / data modem or simple data modem for coupling via suitable connector and isolation circuitry 205 to telephone lines 354 within the customer premises as well as DSL-CO transmission lines 58 and which can be controlled digitally by the host 128 ,
The IP & PBX telephony module 372 may be any known or future developed "PBX on a card" including one or more expansion cards hosting a conventional personal computer 128 running any operating system, giving PBX capabilities and which can be controlled digitally by the host 128 , It may include any additional required known circuitry and software needed to implement IP telephony features.
A DOCSIS modem module may be any known or future developed cable modem conforming to the DOCSIS standard or to any new standard for modems that allows high speed data transmission from customer premises to a headend cable modem and / or the Internet via a CATV HFC cable device and which can be controlled digitally by the host 128 ,
The HFC digital video module 388 can be any digital video receiver that can be digitally controlled by the host 128 and compatible with receiving digitized, compressed video transmitted over HFC. In the system of 4A For example, the HFC digital video module 388 typically the tuner 108 , an A / D converter operating in the matrix 130 is included, the QAM demodulator 146 , the transport demultiplexer 148 and the conditional access circuit 126 included with the shared IP video process 158 to communicate, which runs in software on the host. It may also be the upstream and downstream combiner and isolation circuits 90 and 98 Even though these combiners and isolation circuits are shared by all HFC interface modules in some embodiments.
An HFC analog video module 390 may be any receiver capable of receiving regular, scheduled analog CATV transmissions over HFC which can digitize and compress the data for transmission over the LAN and which can be digitally controlled by the host 128 , In the exemplary embodiment of 4A and 4B would the module 390 typically include the tuner 100 , an A / D converter from the matrix 130 , the video demodulator 138 , the video decoder 114 and MPEG coder 147 , It may also include the upstream and downstream combining and isolation circuits 90 and 98 Although this combination and isolation circuit can be shared by all HFC interface modules in some embodiments.
In some species within the genus of the invention, all HFC interface modules, such as 386 . 388 and 390 , combined in a HFC interface module. The same applies to all expansion modules that connect to the PSTN and extension phone lines, or any modules that connect to the satellite dish.
A satellite digital video on demand module 392 may be any satellite receiver that can be digitally controlled by the host 128 for tuning to and receiving a specific, requested, compressed, digital video on demand transmission from a satellite. In the embodiment of 4A and 4B it closes the tuner 180 , the QPSK demodulator 220 , the transport demultiplexer 184 and the conditional access circuit 186 one.
A satellite analog video module 394 may be any conventional C-band satellite receiver that is modified to receive digital tuning instructions from the host 128 and which is modified to digitize and compress the video program for distribution on a LAN. In the embodiment of 4A and 4B he would include the tuner 114 , the A / D converter 316 , the video demodulator 320 , the video decoder 324 and the MPEG encoder 326 ,
A satellite direct PC module 396 may be any conventional direct PC receiver or any equivalent receiver for receiving IP-packetized data transmitted from a satellite, being able to be digitally controlled by a host computer and the recovered IP packets to send to a routing process that is executed by the host. In the embodiment of 4A and 4B it would include the tuner 302 and the QPSK demodulator 304 ,
A satellite direct TV module 398 may be any conventional DirectPC receiver or equivalent digital satellite broadcast receiver that can receive regular, scheduled, compressed digital TV broadcasts from a satellite, but modified to be digitally controlled by the host 128 for tuning to a requested transmission channel. In the embodiment of 4A and 4B this module would include the tuner 344 , the QAM demodulator 346 , the transport demultiplexer 350 , the transcoder 352 and the conditional access circuit 354 ,
A terrestrial analog NTSC or PAL or SECAM module 400 may be any receiver capable of being digitally tuned by the host computer, which can receive regular, scheduled analog TV transmission via an antenna, and which can digitize and compress for distribution over a LAN. In the embodiment of 4A and 4B it would include the tuner 332 , the A / D converter 334 , the video demodulator 336 , the video decoder 340 and the MPEG encoder 342 ,
the modules defined above that restore digital data
or generate for transmission
close on the LAN
a transcoder for translating
the original bit rate to a lower bitrate where it is needed
due to network load. Similar
Any module that recovers digital data can use the copy protection material
encode, e.g. Video or audio programs, a C5 standard encryption circuit
the digital data before transmission
on the LAN to prevent perfectly unauthorized digital copies
that could occur
if the digital data were to be transmitted in clear form.